initial config manager

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

TODO.md

@@ -1,7 +1,6 @@
 # TODO
 
-- [ ] Implement git style versioning for: synthetic variable, panels, control logic
-- [ ] Implement configuration manager:
+- [ ] **MAJOR** Implement configuration manager:
   - configuration is a set of signals (that can be organized in group and subgroup) that are used to configure a system or a sub system
   - with configuration manager user should be able to:
     - Define and manage configuration sets: delete (keep server side copy of deleted config), create (specifying default to parameters, mandatory, optional etc), edit (with versioning git style) and compare set
@@ -12,17 +11,31 @@
       - user can fork an existing config instance to create a new one
       - user can compare two instances: show unified diff or side by side diff
       - etc...
+    - user can apply and save configuration instances
+    - in logic editor and control loop add nodes to read/write/create/apply config instances
+- [ ] Improve UX:
+  - [x] Synthetic editor:
+    - [x] color code the node link by type
+    - [x] hover on a block in error should show the reason
+    - [x] add proper array functionality
+    - [x] add shortcut to add Signals (S) and nodes (N) with HUD
+  - [ ] Panels:
+    - [x] in view mode the widgets should have no border/bg but blend with background
+    - [ ] add widgets such as toggle switch, table and other industrial hmi widgets
+- [ ] Implement git style versioning for: synthetic variable, panels, control logic:
+  - possibility to fork any version
+  - click to view the version
+  - possibility to view graphical diff between versions (side by side or unified diff)
+  - simple slick versioning pane:
+    - vertical tree like
+    - each version represented by a circle
+    - active (the one currently view/edited) version has circle bigger then rest
+    - selected (the one that will be executed/showed by user) version has circle full, not active only border
+    - unsaved / new version appear with connection line dashed
 - [ ] Implement admin pane: create / manage groups, set users permits, manage auditors etc
 - [ ] Implement new datasources:
+  - [ ] Finalize alarm service
   - [ ] modbus tcp
   - [ ] scpi tcp
-- [ ] Improve UX:
-  - [ ] Synthetic editor:
-    - color code the node link by type
-    - hover on a block in error should show the reason
-    - add proper array functionality
-    - add shortcut to add Signals (S) and nodes (N) with HUD
-  - [ ] Panels:
-    - in view mode the widgets should have no border/bg but blend with background
-    - add widgets such
-- [ ] Implement proper distributed server side nodes to balance load and have redundancy (if a node is not available anymore all its clients migrate seamelessly to another)
+  - [ ] udp? other?
+- [ ] **MAJOR** Implement proper distributed server side nodes to balance load and have redundancy (if a node is not available anymore all its clients migrate seamelessly to another)

cmd/uopi/main.go

@@ -17,6 +17,7 @@ import (
 	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
 	"github.com/uopi/uopi/internal/config"
+	"github.com/uopi/uopi/internal/confmgr"
 	"github.com/uopi/uopi/internal/controllogic"
 	"github.com/uopi/uopi/internal/datasource/epics"
 	"github.com/uopi/uopi/internal/datasource/pva"
@@ -72,6 +73,12 @@ func main() {
 		os.Exit(1)
 	}
 
+	cfgStore, err := confmgr.New(cfg.Server.StorageDir)
+	if err != nil {
+		log.Error("failed to open configuration store", "err", err)
+		os.Exit(1)
+	}
+
 	webFS, err := fs.Sub(web.FS, "dist")
 	if err != nil {
 		log.Error("failed to sub web dist", "err", err)
@@ -194,7 +201,7 @@ func main() {
 	ctrlEngine.SetNotifier(dialogs)
 	ctrlEngine.Reload()
 
-	srv := server.New(cfg.Server.Listen, webFS, brk, synthDS, store, policy, aclStore, ctrlStore, ctrlEngine, dialogs, recorder, cfg.Datasource.EPICS.ChannelFinderURL, cfg.Datasource.EPICS.ArchiveURL, cfg.Server.TrustedUserHeader, log)
+	srv := server.New(cfg.Server.Listen, webFS, brk, synthDS, store, cfgStore, policy, aclStore, ctrlStore, ctrlEngine, dialogs, recorder, cfg.Datasource.EPICS.ChannelFinderURL, cfg.Datasource.EPICS.ArchiveURL, cfg.Server.TrustedUserHeader, log)
 
 	if err := srv.Start(ctx); err != nil {
 		fmt.Fprintf(os.Stderr, "server error: %v\n", err)

docs/FUNCTIONAL_SPEC.md

@@ -192,6 +192,7 @@ When multiple widgets are selected:
 | Histogram | numeric scalar(s) |
 | Bar chart | numeric scalar(s) |
 | Logic analyser | boolean / integer (bitset) |
+| Waveform | 1-D numeric array (latest sample, x-vs-index) |
 
 ### 4.5 Widget Properties (Properties Pane)
 

docs/TECHNICAL_SPEC.md

@@ -41,7 +41,7 @@
 | ---------------- | --------------------------------------------------------------- |
 | `preact` 10      | Virtual DOM UI framework                                        |
 | `uPlot`          | Extremely fast time-series/line plot (canvas-based, < 40 kB)    |
-| `Apache ECharts` | FFT, waterfall, histogram, bar, logic analyser plots            |
+| `Apache ECharts` | FFT, waterfall, histogram, bar, logic analyser, waveform plots   |
 | `uplot.css`      | uPlot default stylesheet                                        |
 
 **Intentionally excluded:** React, Vue, Svelte, Konva, WebGPU, jQuery, npm at runtime.
@@ -234,15 +234,30 @@ endpoints and for any change to a panel's `<logic>` block.
 
 **Built-in node types:**
 
-| Node type    | Parameters                          | Description                                      |
-| ------------ | ----------------------------------- | ------------------------------------------------ |
-| `source`     | `ds`, `name`                        | Reads a signal from any data source              |
-| `gain`       | `factor`                            | Multiplies by a constant                         |
-| `offset`     | `value`                             | Adds a constant                                  |
-| `moving_avg` | `window` (samples)                  | Rolling mean                                     |
-| `lowpass`    | `freq` (Hz), `order` (1–8)          | Cascaded IIR Butterworth-style low-pass filter   |
-| `formula`    | `expr`                              | Inline math expression (variables: `a`, `b`, …) |
-| `lua`        | `script`                            | Arbitrary Lua 5.1 code with persistent state     |
+| Node type        | Parameters                  | In→Out         | Description                                     |
+| ---------------- | --------------------------- | -------------- | ----------------------------------------------- |
+| `source`         | `ds`, `name`                | —              | Reads a signal from any data source             |
+| `gain`           | `gain`                      | elementwise    | Multiplies by a constant                        |
+| `offset`         | `offset`                    | elementwise    | Adds a constant                                 |
+| `add`/`subtract` | —                           | elementwise    | Sum of inputs / `a − b`                         |
+| `multiply`/`divide` | —                        | elementwise    | Product of inputs / `a ÷ b`                     |
+| `clamp`          | `min`, `max`                | elementwise    | Constrains to a range                           |
+| `threshold`      | `threshold`, `high`, `low`  | elementwise    | Comparator output                               |
+| `moving_average` | `window` (samples)          | scalar-only    | Rolling mean                                    |
+| `rms`            | `window` (samples)          | scalar-only    | Rolling RMS                                     |
+| `derivative`     | —                           | scalar-only    | Time derivative (per-sample `dt`)               |
+| `integrate`      | —                           | scalar-only    | Trapezoidal integral                            |
+| `lowpass`        | `freq` (Hz), `order` (1–8)  | scalar-only    | Cascaded IIR Butterworth-style low-pass filter  |
+| `expr`           | `expr`, `vars`              | elementwise    | Inline math expression (named inputs)           |
+| `lua`            | `script`, `vars`            | scalar-only    | Arbitrary Lua 5.1 code with persistent state    |
+| `index`          | `i`                         | array→scalar   | Element `i` of a waveform (bounds-checked)      |
+| `slice`          | `start`, `end`              | array→array    | Sub-range of a waveform (clamped)               |
+| `sum`/`mean`     | —                           | array→scalar   | Σ / average of a waveform                       |
+| `min`/`max`      | —                           | array→scalar   | Reduction of a waveform                         |
+| `length`         | —                           | array→scalar   | Element count of a waveform                     |
+| `fft`            | —                           | array→array    | Magnitude spectrum (zero-padded to next pow-2)  |
+
+**Scalar vs waveform values:** A value flowing through the graph is a `dsp.Sample` — either a scalar `float64` or a `[]float64` waveform (the array-aware counterpart of EPICS `TypeFloat64Array`). *Elementwise* ops broadcast over arrays (scalar inputs act as constants; array inputs must share a length). *Reduction*/*producer* ops (`index`/`slice`/`sum`/…/`fft`) operate natively on waveforms. *Scalar-only* ops (stateful filters + `lua`) reject array inputs, since their per-evaluation state cannot be split across array lanes. `OpOutputType` (`internal/dsp/types.go`) propagates types statically at compile time to reject invalid wirings and to report the synthetic's metadata type; the editor mirrors these rules in `web/src/lib/synthTypes.ts` to colour wires by data type (scalar vs array) and flag type-incompatible links. Runtime `Sample` typing is authoritative.
 
 **Low-pass filter implementation:** Cascaded first-order IIR sections. Each stage computes `y = y_prev + α·(x − y_prev)` where `α = dt / (RC + dt)` and `RC = 1/(2π·fc)`. `dt` is computed per sample from source timestamps so the filter is correct for event-driven (non-uniform) data.
 
@@ -353,7 +368,7 @@ The edit canvas is a free-form HTML div with absolutely positioned widget compon
 View mode renders widgets as absolutely positioned Preact components on a scrollable canvas div:
 
 - Each widget subscribes to its signal store(s) in a `useEffect` and re-renders only when values change.
-- uPlot (time series) and ECharts (histogram, bar, FFT, waterfall, logic analyser) manage their own canvas elements inside their widget component.
+- uPlot (time series) and ECharts (histogram, bar, FFT, waterfall, logic analyser, waveform) manage their own canvas elements inside their widget component. The `waveform` plot renders a waveform (array) signal's latest `[]float64` as an x-vs-index trace, replacing the trace on each update.
 - Plot widgets maintain a rolling ring buffer of 200,000 samples per signal for smooth long-window display.
 - Step-hold interpolation: when multiple signals at different update rates share a plot, the most recent value is carried forward to fill the shared time axis correctly.
 

internal/api/api.go

@@ -18,6 +18,7 @@ import (
 	"github.com/uopi/uopi/internal/access"
 	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
+	"github.com/uopi/uopi/internal/confmgr"
 	"github.com/uopi/uopi/internal/controllogic"
 	"github.com/uopi/uopi/internal/datasource"
 	"github.com/uopi/uopi/internal/datasource/synthetic"
@@ -30,6 +31,7 @@ type Handler struct {
 	broker           *broker.Broker
 	synthetic        *synthetic.Synthetic // nil if not enabled
 	store            *storage.Store
+	cfg              *confmgr.Store
 	policy           *access.Policy
 	acl              *panelacl.Store
 	ctrlLogic        *controllogic.Store
@@ -42,7 +44,7 @@ type Handler struct {
 
 // New creates an API Handler. synth may be nil if the synthetic DS is disabled.
 // rec records system-affecting mutations; pass audit.Nop() to disable auditing.
-func New(b *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, policy *access.Policy, acl *panelacl.Store, ctrlLogic *controllogic.Store, ctrlEngine *controllogic.Engine, rec audit.Recorder, channelFinderURL, archiverURL string, log *slog.Logger) *Handler {
+func New(b *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, cfg *confmgr.Store, policy *access.Policy, acl *panelacl.Store, ctrlLogic *controllogic.Store, ctrlEngine *controllogic.Engine, rec audit.Recorder, channelFinderURL, archiverURL string, log *slog.Logger) *Handler {
 	if rec == nil {
 		rec = audit.Nop()
 	}
@@ -50,6 +52,7 @@ func New(b *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, pol
 		broker:           b,
 		synthetic:        synth,
 		store:            store,
+		cfg:              cfg,
 		policy:           policy,
 		acl:              acl,
 		ctrlLogic:        ctrlLogic,
@@ -109,6 +112,30 @@ func (h *Handler) Register(mux *http.ServeMux, prefix string) {
 	mux.HandleFunc("GET "+prefix+"/controllogic/{id}", h.getControlLogic)
 	mux.HandleFunc("PUT "+prefix+"/controllogic/{id}", h.updateControlLogic)
 	mux.HandleFunc("DELETE "+prefix+"/controllogic/{id}", h.deleteControlLogic)
+	// Configuration manager — config sets (schemas) and instances (values),
+	// both versioned git-style. Mutations are write-gated by the access
+	// middleware; "apply" writes each value to its target signal.
+	mux.HandleFunc("GET "+prefix+"/config/sets", h.listConfigSets)
+	mux.HandleFunc("POST "+prefix+"/config/sets", h.createConfigSet)
+	mux.HandleFunc("GET "+prefix+"/config/sets/{id}", h.getConfigSet)
+	mux.HandleFunc("PUT "+prefix+"/config/sets/{id}", h.updateConfigSet)
+	mux.HandleFunc("DELETE "+prefix+"/config/sets/{id}", h.deleteConfigSet)
+	mux.HandleFunc("GET "+prefix+"/config/sets/{id}/versions", h.listConfigSetVersions)
+	mux.HandleFunc("GET "+prefix+"/config/sets/{id}/versions/{version}", h.getConfigSetVersion)
+	mux.HandleFunc("POST "+prefix+"/config/sets/{id}/versions/{version}/promote", h.promoteConfigSet)
+	mux.HandleFunc("POST "+prefix+"/config/sets/{id}/versions/{version}/fork", h.forkConfigSet)
+	mux.HandleFunc("GET "+prefix+"/config/sets/diff", h.diffConfigSets)
+	mux.HandleFunc("GET "+prefix+"/config/instances", h.listConfigInstances)
+	mux.HandleFunc("POST "+prefix+"/config/instances", h.createConfigInstance)
+	mux.HandleFunc("GET "+prefix+"/config/instances/{id}", h.getConfigInstance)
+	mux.HandleFunc("PUT "+prefix+"/config/instances/{id}", h.updateConfigInstance)
+	mux.HandleFunc("DELETE "+prefix+"/config/instances/{id}", h.deleteConfigInstance)
+	mux.HandleFunc("GET "+prefix+"/config/instances/{id}/versions", h.listConfigInstanceVersions)
+	mux.HandleFunc("GET "+prefix+"/config/instances/{id}/versions/{version}", h.getConfigInstanceVersion)
+	mux.HandleFunc("POST "+prefix+"/config/instances/{id}/versions/{version}/promote", h.promoteConfigInstance)
+	mux.HandleFunc("POST "+prefix+"/config/instances/{id}/versions/{version}/fork", h.forkConfigInstance)
+	mux.HandleFunc("POST "+prefix+"/config/instances/{id}/apply", h.applyConfigInstance)
+	mux.HandleFunc("GET "+prefix+"/config/instances/diff", h.diffConfigInstances)
 }
 
 // ── /me ─────────────────────────────────────────────────────────────────────

internal/api/api_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/uopi/uopi/internal/api"
 	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
+	"github.com/uopi/uopi/internal/confmgr"
 	"github.com/uopi/uopi/internal/controllogic"
 	"github.com/uopi/uopi/internal/datasource/stub"
 	"github.com/uopi/uopi/internal/panelacl"
@@ -53,8 +54,13 @@ func setup(t *testing.T) (*httptest.Server, func()) {
 	}
 	clEngine := controllogic.NewEngine(ctx, brk, clStore, audit.Nop(), log)
 
+	cfgStore, err := confmgr.New(dir)
+	if err != nil {
+		t.Fatal("confmgr.New:", err)
+	}
+
 	mux := http.NewServeMux()
-	api.New(brk, nil, store, access.New("", nil, nil, nil, nil), acl, clStore, clEngine, audit.Nop(), "", "", log).Register(mux, "/api/v1")
+	api.New(brk, nil, store, cfgStore, access.New("", nil, nil, nil, nil), acl, clStore, clEngine, audit.Nop(), "", "", log).Register(mux, "/api/v1")
 
 	srv := httptest.NewServer(mux)
 	return srv, func() {

internal/api/confmgr.go

@@ -0,0 +1,446 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/uopi/uopi/internal/confmgr"
+)
+
+// configEnabled guards every config-manager handler; the store is always
+// constructed today, but the nil check keeps the handlers safe if it is ever
+// made optional.
+func (h *Handler) configEnabled(w http.ResponseWriter) bool {
+	if h.cfg == nil {
+		jsonError(w, http.StatusServiceUnavailable, "configuration manager not enabled")
+		return false
+	}
+	return true
+}
+
+func pathVersion(r *http.Request) (int, error) {
+	return strconv.Atoi(r.PathValue("version"))
+}
+
+func configStatus(err error) int {
+	if errors.Is(err, confmgr.ErrNotFound) {
+		return http.StatusNotFound
+	}
+	return http.StatusBadRequest
+}
+
+// ── config sets ─────────────────────────────────────────────────────────────
+
+func (h *Handler) listConfigSets(w http.ResponseWriter, _ *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	sets, err := h.cfg.List(confmgr.KindSet)
+	if err != nil {
+		jsonError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	jsonOK(w, sets)
+}
+
+func (h *Handler) getConfigSet(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	set, err := h.cfg.GetSet(r.PathValue("id"))
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	jsonOK(w, set)
+}
+
+func (h *Handler) createConfigSet(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	var set confmgr.ConfigSet
+	if err := json.NewDecoder(r.Body).Decode(&set); err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
+		return
+	}
+	set.ID = ""
+	set.Owner = caller(r)
+	out, err := h.cfg.CreateSet(set, r.URL.Query().Get("tag"))
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.set.create", out.ID+" "+out.Name)
+	w.WriteHeader(http.StatusCreated)
+	jsonOK(w, out)
+}
+
+func (h *Handler) updateConfigSet(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	id := r.PathValue("id")
+	var set confmgr.ConfigSet
+	if err := json.NewDecoder(r.Body).Decode(&set); err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
+		return
+	}
+	out, err := h.cfg.UpdateSet(id, set, r.URL.Query().Get("tag"))
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.set.update", out.ID+" v"+strconv.Itoa(out.Version))
+	jsonOK(w, out)
+}
+
+func (h *Handler) deleteConfigSet(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	id := r.PathValue("id")
+	if err := h.cfg.Delete(confmgr.KindSet, id); err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.set.delete", id)
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func (h *Handler) listConfigSetVersions(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	versions, err := h.cfg.Versions(confmgr.KindSet, r.PathValue("id"))
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	jsonOK(w, versions)
+}
+
+func (h *Handler) getConfigSetVersion(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	version, err := pathVersion(r)
+	if err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid version")
+		return
+	}
+	set, err := h.cfg.GetSetVersion(r.PathValue("id"), version)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	jsonOK(w, set)
+}
+
+func (h *Handler) promoteConfigSet(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	version, err := pathVersion(r)
+	if err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid version")
+		return
+	}
+	id := r.PathValue("id")
+	if err := h.cfg.Promote(confmgr.KindSet, id, version); err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.set.promote", id+" v"+strconv.Itoa(version))
+	set, err := h.cfg.GetSet(id)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	jsonOK(w, set)
+}
+
+func (h *Handler) forkConfigSet(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	version, err := pathVersion(r)
+	if err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid version")
+		return
+	}
+	id := r.PathValue("id")
+	newID, err := h.cfg.Fork(confmgr.KindSet, id, version)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.set.fork", id+" v"+strconv.Itoa(version)+" -> "+newID)
+	set, err := h.cfg.GetSet(newID)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	w.WriteHeader(http.StatusCreated)
+	jsonOK(w, set)
+}
+
+// diffConfigSets compares two set revisions. Query params: a, b (ids);
+// optional av, bv (versions, default current).
+func (h *Handler) diffConfigSets(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	q := r.URL.Query()
+	left, err := h.resolveSet(q.Get("a"), q.Get("av"))
+	if err != nil {
+		jsonError(w, configStatus(err), "left set: "+err.Error())
+		return
+	}
+	right, err := h.resolveSet(q.Get("b"), q.Get("bv"))
+	if err != nil {
+		jsonError(w, configStatus(err), "right set: "+err.Error())
+		return
+	}
+	jsonOK(w, confmgr.DiffSets(left, right))
+}
+
+func (h *Handler) resolveSet(id, version string) (confmgr.ConfigSet, error) {
+	if id == "" {
+		return confmgr.ConfigSet{}, errors.New("missing set id")
+	}
+	if version == "" {
+		return h.cfg.GetSet(id)
+	}
+	v, err := strconv.Atoi(version)
+	if err != nil {
+		return confmgr.ConfigSet{}, errors.New("invalid version")
+	}
+	return h.cfg.GetSetVersion(id, v)
+}
+
+// ── config instances ────────────────────────────────────────────────────────
+
+func (h *Handler) listConfigInstances(w http.ResponseWriter, _ *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	insts, err := h.cfg.List(confmgr.KindInstance)
+	if err != nil {
+		jsonError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	jsonOK(w, insts)
+}
+
+func (h *Handler) getConfigInstance(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	inst, err := h.cfg.GetInstance(r.PathValue("id"))
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	jsonOK(w, inst)
+}
+
+func (h *Handler) createConfigInstance(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	var inst confmgr.ConfigInstance
+	if err := json.NewDecoder(r.Body).Decode(&inst); err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
+		return
+	}
+	inst.ID = ""
+	inst.Owner = caller(r)
+	out, err := h.cfg.CreateInstance(inst, r.URL.Query().Get("tag"))
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.instance.create", out.ID+" "+out.Name)
+	w.WriteHeader(http.StatusCreated)
+	jsonOK(w, out)
+}
+
+func (h *Handler) updateConfigInstance(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	id := r.PathValue("id")
+	var inst confmgr.ConfigInstance
+	if err := json.NewDecoder(r.Body).Decode(&inst); err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid JSON: "+err.Error())
+		return
+	}
+	out, err := h.cfg.UpdateInstance(id, inst, r.URL.Query().Get("tag"))
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.instance.update", out.ID+" v"+strconv.Itoa(out.Version))
+	jsonOK(w, out)
+}
+
+func (h *Handler) deleteConfigInstance(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	id := r.PathValue("id")
+	if err := h.cfg.Delete(confmgr.KindInstance, id); err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.instance.delete", id)
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func (h *Handler) listConfigInstanceVersions(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	versions, err := h.cfg.Versions(confmgr.KindInstance, r.PathValue("id"))
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	jsonOK(w, versions)
+}
+
+func (h *Handler) getConfigInstanceVersion(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	version, err := pathVersion(r)
+	if err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid version")
+		return
+	}
+	inst, err := h.cfg.GetInstanceVersion(r.PathValue("id"), version)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	jsonOK(w, inst)
+}
+
+func (h *Handler) promoteConfigInstance(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	version, err := pathVersion(r)
+	if err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid version")
+		return
+	}
+	id := r.PathValue("id")
+	if err := h.cfg.Promote(confmgr.KindInstance, id, version); err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.instance.promote", id+" v"+strconv.Itoa(version))
+	inst, err := h.cfg.GetInstance(id)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	jsonOK(w, inst)
+}
+
+func (h *Handler) forkConfigInstance(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	version, err := pathVersion(r)
+	if err != nil {
+		jsonError(w, http.StatusBadRequest, "invalid version")
+		return
+	}
+	id := r.PathValue("id")
+	newID, err := h.cfg.Fork(confmgr.KindInstance, id, version)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	h.recordMutation(r, "config.instance.fork", id+" v"+strconv.Itoa(version)+" -> "+newID)
+	inst, err := h.cfg.GetInstance(newID)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	w.WriteHeader(http.StatusCreated)
+	jsonOK(w, inst)
+}
+
+// applyConfigInstance writes every resolvable parameter value of an instance to
+// its target signal via the broker. Per-parameter outcomes are returned so a
+// partial apply is reported faithfully.
+func (h *Handler) applyConfigInstance(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	id := r.PathValue("id")
+	inst, err := h.cfg.GetInstance(id)
+	if err != nil {
+		jsonError(w, configStatus(err), err.Error())
+		return
+	}
+	set, err := h.cfg.SetForInstance(inst)
+	if err != nil {
+		jsonError(w, configStatus(err), "load set: "+err.Error())
+		return
+	}
+	ctx, cancel := context.WithTimeout(r.Context(), 15*time.Second)
+	defer cancel()
+	write := func(ds, signal string, value any) error {
+		src, ok := h.broker.Source(ds)
+		if !ok {
+			return errors.New("unknown data source: " + ds)
+		}
+		return src.Write(ctx, signal, value)
+	}
+	res := confmgr.Apply(set, inst, write)
+	h.recordMutation(r, "config.instance.apply", id+" applied="+strconv.Itoa(res.Applied)+" failed="+strconv.Itoa(res.Failed))
+	jsonOK(w, res)
+}
+
+// diffConfigInstances compares two instance revisions. Query params: a, b
+// (ids); optional av, bv (versions, default current).
+func (h *Handler) diffConfigInstances(w http.ResponseWriter, r *http.Request) {
+	if !h.configEnabled(w) {
+		return
+	}
+	q := r.URL.Query()
+	left, err := h.resolveInstance(q.Get("a"), q.Get("av"))
+	if err != nil {
+		jsonError(w, configStatus(err), "left instance: "+err.Error())
+		return
+	}
+	right, err := h.resolveInstance(q.Get("b"), q.Get("bv"))
+	if err != nil {
+		jsonError(w, configStatus(err), "right instance: "+err.Error())
+		return
+	}
+	jsonOK(w, confmgr.DiffInstances(left, right))
+}
+
+func (h *Handler) resolveInstance(id, version string) (confmgr.ConfigInstance, error) {
+	if id == "" {
+		return confmgr.ConfigInstance{}, errors.New("missing instance id")
+	}
+	if version == "" {
+		return h.cfg.GetInstance(id)
+	}
+	v, err := strconv.Atoi(version)
+	if err != nil {
+		return confmgr.ConfigInstance{}, errors.New("invalid version")
+	}
+	return h.cfg.GetInstanceVersion(id, v)
+}

internal/api/confmgr_test.go

@@ -0,0 +1,107 @@
+package api_test
+
+import (
+	"net/http"
+	"testing"
+)
+
+// TestConfigSetCRUD exercises create → get → version → apply over HTTP, using
+// the stub data source's writable "setpoint" signal as the apply target.
+func TestConfigManagerEndToEnd(t *testing.T) {
+	srv, teardown := setup(t)
+	defer teardown()
+
+	// Create a config set targeting the stub's writable setpoint.
+	setBody := map[string]any{
+		"name": "Stub PSU",
+		"parameters": []map[string]any{
+			{"key": "sp", "ds": "stub", "signal": "setpoint", "type": "float64", "default": 42.0, "mandatory": true, "min": 0.0, "max": 100.0},
+		},
+	}
+	resp := postJSON(t, srv, "/api/v1/config/sets", setBody)
+	assertStatus(t, resp, http.StatusCreated)
+	var set struct {
+		ID      string `json:"id"`
+		Version int    `json:"version"`
+	}
+	readJSON(t, resp, &set)
+	if set.ID == "" || set.Version != 1 {
+		t.Fatalf("unexpected created set: %+v", set)
+	}
+
+	// List sets includes it.
+	resp = get(t, srv, "/api/v1/config/sets")
+	assertStatus(t, resp, http.StatusOK)
+	var sets []map[string]any
+	readJSON(t, resp, &sets)
+	if len(sets) != 1 {
+		t.Fatalf("want 1 set, got %d", len(sets))
+	}
+
+	// Create an instance assigning a concrete value.
+	instBody := map[string]any{
+		"name":   "nominal",
+		"setId":  set.ID,
+		"values": map[string]any{"sp": 73.0},
+	}
+	resp = postJSON(t, srv, "/api/v1/config/instances", instBody)
+	assertStatus(t, resp, http.StatusCreated)
+	var inst struct {
+		ID string `json:"id"`
+	}
+	readJSON(t, resp, &inst)
+	if inst.ID == "" {
+		t.Fatal("instance missing id")
+	}
+
+	// Apply writes the value to the target signal.
+	resp = postJSON(t, srv, "/api/v1/config/instances/"+inst.ID+"/apply", nil)
+	assertStatus(t, resp, http.StatusOK)
+	var res struct {
+		Applied int `json:"applied"`
+		Failed  int `json:"failed"`
+		Entries []struct {
+			Signal string `json:"signal"`
+			OK     bool   `json:"ok"`
+		} `json:"entries"`
+	}
+	readJSON(t, resp, &res)
+	if res.Applied != 1 || res.Failed != 0 {
+		t.Fatalf("apply summary: applied=%d failed=%d", res.Applied, res.Failed)
+	}
+	if len(res.Entries) != 1 || res.Entries[0].Signal != "setpoint" || !res.Entries[0].OK {
+		t.Errorf("unexpected apply entries: %+v", res.Entries)
+	}
+
+	// Delete the set soft-deletes it.
+	resp = deleteReq(t, srv, "/api/v1/config/sets/"+set.ID)
+	assertStatus(t, resp, http.StatusNoContent)
+	resp = get(t, srv, "/api/v1/config/sets/"+set.ID)
+	assertStatus(t, resp, http.StatusNotFound)
+}
+
+// TestConfigInstanceRejectsInvalidValue verifies server-side validation against
+// the bound set (value above the parameter's max).
+func TestConfigInstanceRejectsInvalidValue(t *testing.T) {
+	srv, teardown := setup(t)
+	defer teardown()
+
+	resp := postJSON(t, srv, "/api/v1/config/sets", map[string]any{
+		"name": "S",
+		"parameters": []map[string]any{
+			{"key": "sp", "ds": "stub", "signal": "setpoint", "type": "float64", "max": 10.0},
+		},
+	})
+	assertStatus(t, resp, http.StatusCreated)
+	var set struct {
+		ID string `json:"id"`
+	}
+	readJSON(t, resp, &set)
+
+	resp = postJSON(t, srv, "/api/v1/config/instances", map[string]any{
+		"name":   "bad",
+		"setId":  set.ID,
+		"values": map[string]any{"sp": 999.0},
+	})
+	assertStatus(t, resp, http.StatusBadRequest)
+}

internal/confmgr/apply.go

@@ -0,0 +1,55 @@
+package confmgr
+
+// WriteFunc writes a resolved value to a target signal. The API layer supplies
+// a closure backed by the broker/datasource so confmgr stays decoupled from the
+// transport.
+type WriteFunc func(ds, signal string, value any) error
+
+// ApplyEntry records the outcome of writing one parameter.
+type ApplyEntry struct {
+	Key     string `json:"key"`
+	DS      string `json:"ds"`
+	Signal  string `json:"signal"`
+	Value   any    `json:"value,omitempty"`
+	OK      bool   `json:"ok"`
+	Skipped bool   `json:"skipped,omitempty"`
+	Error   string `json:"error,omitempty"`
+}
+
+// ApplyResult summarises an apply run.
+type ApplyResult struct {
+	InstanceID string       `json:"instanceId"`
+	SetID      string       `json:"setId"`
+	Entries    []ApplyEntry `json:"entries"`
+	Applied    int          `json:"applied"`
+	Failed     int          `json:"failed"`
+	Skipped    int          `json:"skipped"`
+}
+
+// Apply writes every resolvable parameter value of an instance to its target
+// signal via write. Optional parameters with no value and no default are
+// skipped. Individual write failures are recorded per-entry rather than
+// aborting the whole apply, so a partial apply is reported faithfully.
+func Apply(set ConfigSet, inst ConfigInstance, write WriteFunc) ApplyResult {
+	res := ApplyResult{InstanceID: inst.ID, SetID: set.ID, Entries: make([]ApplyEntry, 0, len(set.Parameters))}
+	for _, p := range set.Parameters {
+		e := ApplyEntry{Key: p.Key, DS: p.DS, Signal: p.Signal}
+		v, ok := inst.Resolve(p)
+		if !ok {
+			e.Skipped = true
+			res.Skipped++
+			res.Entries = append(res.Entries, e)
+			continue
+		}
+		e.Value = v
+		if err := write(p.DS, p.Signal, v); err != nil {
+			e.Error = err.Error()
+			res.Failed++
+		} else {
+			e.OK = true
+			res.Applied++
+		}
+		res.Entries = append(res.Entries, e)
+	}
+	return res
+}

internal/confmgr/apply_test.go

@@ -0,0 +1,77 @@
+package confmgr
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestApplyWritesValues(t *testing.T) {
+	set := ConfigSet{
+		ID:   "set1",
+		Name: "s",
+		Parameters: []Parameter{
+			{Key: "v", DS: "epics", Signal: "PSU:V", Type: TypeFloat, Default: 12.0},
+			{Key: "en", DS: "epics", Signal: "PSU:EN", Type: TypeBool},
+			{Key: "opt", DS: "epics", Signal: "PSU:OPT", Type: TypeFloat}, // no value, no default → skipped
+		},
+	}
+	inst := ConfigInstance{ID: "i1", SetID: "set1", Values: map[string]any{"v": 24.0, "en": true}}
+
+	type write struct {
+		ds, sig string
+		val     any
+	}
+	var writes []write
+	res := Apply(set, inst, func(ds, signal string, value any) error {
+		writes = append(writes, write{ds, signal, value})
+		return nil
+	})
+
+	if res.Applied != 2 || res.Skipped != 1 || res.Failed != 0 {
+		t.Fatalf("summary: applied=%d skipped=%d failed=%d", res.Applied, res.Skipped, res.Failed)
+	}
+	if len(writes) != 2 {
+		t.Fatalf("want 2 writes, got %d", len(writes))
+	}
+	if writes[0].sig != "PSU:V" || writes[0].val != 24.0 {
+		t.Errorf("first write: %+v", writes[0])
+	}
+}
+
+func TestApplyUsesDefaultWhenNoValue(t *testing.T) {
+	set := ConfigSet{
+		ID: "set1", Name: "s",
+		Parameters: []Parameter{{Key: "v", DS: "d", Signal: "S", Type: TypeFloat, Default: 7.0}},
+	}
+	inst := ConfigInstance{ID: "i", SetID: "set1", Values: map[string]any{}}
+	var got any
+	res := Apply(set, inst, func(_, _ string, value any) error { got = value; return nil })
+	if res.Applied != 1 || got != 7.0 {
+		t.Errorf("want default 7.0 applied, got %v (applied=%d)", got, res.Applied)
+	}
+}
+
+func TestApplyRecordsFailures(t *testing.T) {
+	set := ConfigSet{
+		ID: "set1", Name: "s",
+		Parameters: []Parameter{
+			{Key: "a", DS: "d", Signal: "A", Type: TypeFloat, Default: 1.0},
+			{Key: "b", DS: "d", Signal: "B", Type: TypeFloat, Default: 2.0},
+		},
+	}
+	inst := ConfigInstance{ID: "i", SetID: "set1", Values: map[string]any{}}
+	res := Apply(set, inst, func(_, signal string, _ any) error {
+		if signal == "B" {
+			return errors.New("write rejected")
+		}
+		return nil
+	})
+	if res.Applied != 1 || res.Failed != 1 {
+		t.Fatalf("want applied=1 failed=1, got applied=%d failed=%d", res.Applied, res.Failed)
+	}
+	for _, e := range res.Entries {
+		if e.Key == "b" && (e.OK || e.Error == "") {
+			t.Errorf("entry b should record failure: %+v", e)
+		}
+	}
+}

internal/confmgr/diff.go

@@ -0,0 +1,140 @@
+package confmgr
+
+import (
+	"fmt"
+	"sort"
+)
+
+// ChangeStatus classifies a single diff entry.
+type ChangeStatus string
+
+const (
+	StatusAdded     ChangeStatus = "added"
+	StatusRemoved   ChangeStatus = "removed"
+	StatusChanged   ChangeStatus = "changed"
+	StatusUnchanged ChangeStatus = "unchanged"
+)
+
+// SetDiffEntry is one parameter-level difference between two config sets.
+type SetDiffEntry struct {
+	Key    string       `json:"key"`
+	Status ChangeStatus `json:"status"`
+	Left   *Parameter   `json:"left,omitempty"`
+	Right  *Parameter   `json:"right,omitempty"`
+}
+
+// InstanceDiffEntry is one value-level difference between two config instances.
+type InstanceDiffEntry struct {
+	Key    string       `json:"key"`
+	Status ChangeStatus `json:"status"`
+	Left   any          `json:"left,omitempty"`
+	Right  any          `json:"right,omitempty"`
+}
+
+// DiffSets compares two config sets parameter-by-parameter (keyed by Key),
+// returning entries sorted by key. Both sides are included so the frontend can
+// render either unified or side-by-side.
+func DiffSets(left, right ConfigSet) []SetDiffEntry {
+	keys := map[string]bool{}
+	li := map[string]Parameter{}
+	ri := map[string]Parameter{}
+	for _, p := range left.Parameters {
+		li[p.Key] = p
+		keys[p.Key] = true
+	}
+	for _, p := range right.Parameters {
+		ri[p.Key] = p
+		keys[p.Key] = true
+	}
+	out := make([]SetDiffEntry, 0, len(keys))
+	for k := range keys {
+		l, lok := li[k]
+		r, rok := ri[k]
+		e := SetDiffEntry{Key: k}
+		switch {
+		case lok && !rok:
+			e.Status = StatusRemoved
+			lp := l
+			e.Left = &lp
+		case !lok && rok:
+			e.Status = StatusAdded
+			rp := r
+			e.Right = &rp
+		default:
+			lp, rp := l, r
+			e.Left, e.Right = &lp, &rp
+			if paramEqual(l, r) {
+				e.Status = StatusUnchanged
+			} else {
+				e.Status = StatusChanged
+			}
+		}
+		out = append(out, e)
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Key < out[j].Key })
+	return out
+}
+
+// DiffInstances compares two config instances value-by-value (keyed by
+// parameter key), returning entries sorted by key.
+func DiffInstances(left, right ConfigInstance) []InstanceDiffEntry {
+	keys := map[string]bool{}
+	for k := range left.Values {
+		keys[k] = true
+	}
+	for k := range right.Values {
+		keys[k] = true
+	}
+	out := make([]InstanceDiffEntry, 0, len(keys))
+	for k := range keys {
+		lv, lok := left.Values[k]
+		rv, rok := right.Values[k]
+		e := InstanceDiffEntry{Key: k, Left: lv, Right: rv}
+		switch {
+		case lok && !rok:
+			e.Status = StatusRemoved
+		case !lok && rok:
+			e.Status = StatusAdded
+		case valueEqual(lv, rv):
+			e.Status = StatusUnchanged
+		default:
+			e.Status = StatusChanged
+		}
+		out = append(out, e)
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Key < out[j].Key })
+	return out
+}
+
+func paramEqual(a, b Parameter) bool {
+	if a.Label != b.Label || a.Group != b.Group || a.Subgroup != b.Subgroup ||
+		a.DS != b.DS || a.Signal != b.Signal || a.Type != b.Type ||
+		a.Mandatory != b.Mandatory || a.Unit != b.Unit || a.Description != b.Description {
+		return false
+	}
+	if !valueEqual(a.Default, b.Default) || !floatPtrEqual(a.Min, b.Min) || !floatPtrEqual(a.Max, b.Max) {
+		return false
+	}
+	if len(a.EnumValues) != len(b.EnumValues) {
+		return false
+	}
+	for i := range a.EnumValues {
+		if a.EnumValues[i] != b.EnumValues[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func floatPtrEqual(a, b *float64) bool {
+	if a == nil || b == nil {
+		return a == b
+	}
+	return *a == *b
+}
+
+// valueEqual compares two JSON-decoded scalar values for diff purposes by
+// rendering them to a canonical string.
+func valueEqual(a, b any) bool {
+	return fmt.Sprintf("%v", a) == fmt.Sprintf("%v", b)
+}

internal/confmgr/diff_test.go

@@ -0,0 +1,55 @@
+package confmgr
+
+import "testing"
+
+func TestDiffSets(t *testing.T) {
+	left := ConfigSet{Parameters: []Parameter{
+		{Key: "a", DS: "d", Signal: "A", Type: TypeFloat, Default: 1.0},
+		{Key: "b", DS: "d", Signal: "B", Type: TypeFloat},
+	}}
+	right := ConfigSet{Parameters: []Parameter{
+		{Key: "a", DS: "d", Signal: "A", Type: TypeFloat, Default: 2.0}, // changed default
+		{Key: "c", DS: "d", Signal: "C", Type: TypeFloat},               // added
+	}}
+	diff := DiffSets(left, right)
+	got := map[string]ChangeStatus{}
+	for _, e := range diff {
+		got[e.Key] = e.Status
+	}
+	if got["a"] != StatusChanged {
+		t.Errorf("a: want changed, got %s", got["a"])
+	}
+	if got["b"] != StatusRemoved {
+		t.Errorf("b: want removed, got %s", got["b"])
+	}
+	if got["c"] != StatusAdded {
+		t.Errorf("c: want added, got %s", got["c"])
+	}
+}
+
+func TestDiffSetsUnchanged(t *testing.T) {
+	p := Parameter{Key: "a", DS: "d", Signal: "A", Type: TypeFloat, Default: 1.0}
+	diff := DiffSets(ConfigSet{Parameters: []Parameter{p}}, ConfigSet{Parameters: []Parameter{p}})
+	if len(diff) != 1 || diff[0].Status != StatusUnchanged {
+		t.Errorf("want single unchanged entry, got %+v", diff)
+	}
+}
+
+func TestDiffInstances(t *testing.T) {
+	left := ConfigInstance{Values: map[string]any{"a": 1.0, "b": "x"}}
+	right := ConfigInstance{Values: map[string]any{"a": 2.0, "c": true}}
+	diff := DiffInstances(left, right)
+	got := map[string]ChangeStatus{}
+	for _, e := range diff {
+		got[e.Key] = e.Status
+	}
+	if got["a"] != StatusChanged {
+		t.Errorf("a: want changed, got %s", got["a"])
+	}
+	if got["b"] != StatusRemoved {
+		t.Errorf("b: want removed, got %s", got["b"])
+	}
+	if got["c"] != StatusAdded {
+		t.Errorf("c: want added, got %s", got["c"])
+	}
+}

internal/confmgr/model.go

@@ -0,0 +1,225 @@
+// Package confmgr implements the configuration manager: versioned, git-style
+// configuration Sets (schemas of parameters bound to target signals) and
+// configuration Instances (concrete values for a set), persisted as versioned
+// JSON files. Applying an instance writes each value to its target signal.
+package confmgr
+
+import (
+	"fmt"
+	"math"
+	"slices"
+	"strconv"
+	"strings"
+)
+
+// ParamType enumerates the value kinds a parameter may hold.
+type ParamType string
+
+const (
+	TypeFloat  ParamType = "float64"
+	TypeInt    ParamType = "int64"
+	TypeBool   ParamType = "bool"
+	TypeString ParamType = "string"
+	TypeEnum   ParamType = "enum"
+)
+
+func (t ParamType) valid() bool {
+	switch t {
+	case TypeFloat, TypeInt, TypeBool, TypeString, TypeEnum:
+		return true
+	}
+	return false
+}
+
+// Parameter is one entry in a configuration set's schema. It names a target
+// signal (DS + Signal), a value type, an optional default, and validation
+// metadata. Parameters may be grouped for presentation via Group/Subgroup.
+type Parameter struct {
+	Key         string    `json:"key"`              // unique within the set
+	Label       string    `json:"label,omitempty"`  // human-friendly name
+	Group       string    `json:"group,omitempty"`  // top-level grouping
+	Subgroup    string    `json:"subgroup,omitempty"`
+	DS          string    `json:"ds"`               // target data source
+	Signal      string    `json:"signal"`           // target signal name
+	Type        ParamType `json:"type"`             // value kind
+	Default     any       `json:"default,omitempty"`
+	Mandatory   bool      `json:"mandatory,omitempty"`
+	Min         *float64  `json:"min,omitempty"`         // numeric lower bound
+	Max         *float64  `json:"max,omitempty"`         // numeric upper bound
+	EnumValues  []string  `json:"enumValues,omitempty"`  // allowed values for enum
+	Unit        string    `json:"unit,omitempty"`
+	Description string    `json:"description,omitempty"`
+}
+
+// ConfigSet is the schema half of the two-tier model: an ordered list of
+// parameters bound to target signals. It is versioned git-style.
+type ConfigSet struct {
+	ID          string      `json:"id"`
+	Name        string      `json:"name"`
+	Description string      `json:"description,omitempty"`
+	Version     int         `json:"version"`
+	Tag         string      `json:"tag,omitempty"`
+	Owner       string      `json:"owner,omitempty"`
+	Parameters  []Parameter `json:"parameters"`
+}
+
+// ConfigInstance is the value half: concrete values for a set's parameters,
+// keyed by parameter key. SetID pins the schema it belongs to; SetVersion pins
+// the schema revision (0 means "track current"). It is versioned git-style.
+type ConfigInstance struct {
+	ID         string         `json:"id"`
+	Name       string         `json:"name"`
+	SetID      string         `json:"setId"`
+	SetVersion int            `json:"setVersion,omitempty"` // 0 = current set version
+	Version    int            `json:"version"`
+	Tag        string         `json:"tag,omitempty"`
+	Owner      string         `json:"owner,omitempty"`
+	Values     map[string]any `json:"values"`
+}
+
+// Validate checks structural invariants of a config set: non-empty name,
+// unique non-empty parameter keys, valid types, a target signal per parameter,
+// and well-formed enum/default metadata.
+func (s ConfigSet) Validate() error {
+	if strings.TrimSpace(s.Name) == "" {
+		return fmt.Errorf("config set name must not be empty")
+	}
+	seen := make(map[string]bool, len(s.Parameters))
+	for i, p := range s.Parameters {
+		if strings.TrimSpace(p.Key) == "" {
+			return fmt.Errorf("parameter %d: key must not be empty", i)
+		}
+		if seen[p.Key] {
+			return fmt.Errorf("duplicate parameter key %q", p.Key)
+		}
+		seen[p.Key] = true
+		if !p.Type.valid() {
+			return fmt.Errorf("parameter %q: invalid type %q", p.Key, p.Type)
+		}
+		if strings.TrimSpace(p.DS) == "" || strings.TrimSpace(p.Signal) == "" {
+			return fmt.Errorf("parameter %q: target ds and signal are required", p.Key)
+		}
+		if p.Type == TypeEnum && len(p.EnumValues) == 0 {
+			return fmt.Errorf("parameter %q: enum type requires enumValues", p.Key)
+		}
+		if p.Min != nil && p.Max != nil && *p.Min > *p.Max {
+			return fmt.Errorf("parameter %q: min %v greater than max %v", p.Key, *p.Min, *p.Max)
+		}
+		if p.Default != nil {
+			if err := p.checkValue(p.Default); err != nil {
+				return fmt.Errorf("parameter %q default: %w", p.Key, err)
+			}
+		}
+	}
+	return nil
+}
+
+// param returns the parameter with the given key, or false.
+func (s ConfigSet) param(key string) (Parameter, bool) {
+	for _, p := range s.Parameters {
+		if p.Key == key {
+			return p, true
+		}
+	}
+	return Parameter{}, false
+}
+
+// ValidateAgainst checks an instance against its set: every value references a
+// known parameter and is type/range valid; every mandatory parameter without a
+// default has a value.
+func (inst ConfigInstance) ValidateAgainst(set ConfigSet) error {
+	for key, v := range inst.Values {
+		p, ok := set.param(key)
+		if !ok {
+			return fmt.Errorf("value for unknown parameter %q", key)
+		}
+		if err := p.checkValue(v); err != nil {
+			return fmt.Errorf("parameter %q: %w", key, err)
+		}
+	}
+	for _, p := range set.Parameters {
+		if !p.Mandatory {
+			continue
+		}
+		if _, ok := inst.Values[p.Key]; ok {
+			continue
+		}
+		if p.Default == nil {
+			return fmt.Errorf("mandatory parameter %q has no value", p.Key)
+		}
+	}
+	return nil
+}
+
+// Resolve returns the effective value for a parameter: the instance value when
+// present, otherwise the parameter default. The second result is false when no
+// value is available (optional parameter, no default).
+func (inst ConfigInstance) Resolve(p Parameter) (any, bool) {
+	if v, ok := inst.Values[p.Key]; ok {
+		return v, true
+	}
+	if p.Default != nil {
+		return p.Default, true
+	}
+	return nil, false
+}
+
+// checkValue verifies a value matches the parameter's type and constraints.
+func (p Parameter) checkValue(v any) error {
+	switch p.Type {
+	case TypeFloat, TypeInt:
+		f, err := toFloat(v)
+		if err != nil {
+			return err
+		}
+		if p.Type == TypeInt && f != math.Trunc(f) {
+			return fmt.Errorf("value %v is not an integer", f)
+		}
+		if p.Min != nil && f < *p.Min {
+			return fmt.Errorf("value %v below minimum %v", f, *p.Min)
+		}
+		if p.Max != nil && f > *p.Max {
+			return fmt.Errorf("value %v above maximum %v", f, *p.Max)
+		}
+	case TypeBool:
+		if _, ok := v.(bool); !ok {
+			return fmt.Errorf("value %v is not a bool", v)
+		}
+	case TypeString:
+		if _, ok := v.(string); !ok {
+			return fmt.Errorf("value %v is not a string", v)
+		}
+	case TypeEnum:
+		s, ok := v.(string)
+		if !ok {
+			return fmt.Errorf("enum value %v is not a string", v)
+		}
+		if !slices.Contains(p.EnumValues, s) {
+			return fmt.Errorf("value %q is not an allowed enum value", s)
+		}
+	}
+	return nil
+}
+
+// toFloat coerces a JSON-decoded numeric value to float64. JSON unmarshalling
+// yields float64 for numbers, but values may also arrive as int or string.
+func toFloat(v any) (float64, error) {
+	switch n := v.(type) {
+	case float64:
+		return n, nil
+	case float32:
+		return float64(n), nil
+	case int:
+		return float64(n), nil
+	case int64:
+		return float64(n), nil
+	case string:
+		f, err := strconv.ParseFloat(n, 64)
+		if err != nil {
+			return 0, fmt.Errorf("value %q is not numeric", n)
+		}
+		return f, nil
+	default:
+		return 0, fmt.Errorf("value %v is not numeric", v)
+	}
+}

internal/confmgr/store.go

@@ -0,0 +1,550 @@
+package confmgr
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+	"unicode"
+)
+
+// ErrNotFound is returned when the requested set or instance does not exist.
+var ErrNotFound = errors.New("config object not found")
+
+// Kind selects which collection a store operation targets.
+type Kind int
+
+const (
+	KindSet Kind = iota
+	KindInstance
+)
+
+func (k Kind) sub() string {
+	if k == KindInstance {
+		return "instances"
+	}
+	return "sets"
+}
+
+// Meta is the lightweight listing representation.
+type Meta struct {
+	ID      string `json:"id"`
+	Name    string `json:"name"`
+	Version int    `json:"version"`
+}
+
+// VersionMeta describes a single persisted revision.
+type VersionMeta struct {
+	Version int       `json:"version"`
+	Name    string    `json:"name"`
+	Tag     string    `json:"tag,omitempty"`
+	Current bool      `json:"current"`
+	SavedAt time.Time `json:"savedAt"`
+}
+
+// Store persists configuration sets and instances as versioned JSON files
+// under {storageDir}/configs/{sets,instances}/. Each object lives in
+// {id}.json with prior revisions preserved as {id}.v{N}.json backups, exactly
+// mirroring the panel storage versioning scheme.
+type Store struct {
+	rootDir string
+	dirs    map[Kind]string
+}
+
+// New opens (and creates, if needed) the configs storage directories.
+func New(storageDir string) (*Store, error) {
+	s := &Store{rootDir: storageDir, dirs: map[Kind]string{}}
+	for _, k := range []Kind{KindSet, KindInstance} {
+		dir := filepath.Join(storageDir, "configs", k.sub())
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			return nil, fmt.Errorf("create %s dir: %w", k.sub(), err)
+		}
+		s.dirs[k] = dir
+	}
+	return s, nil
+}
+
+// header parses the metadata fields shared by sets and instances.
+type header struct {
+	ID      string `json:"id"`
+	Name    string `json:"name"`
+	Version int    `json:"version"`
+	Tag     string `json:"tag"`
+}
+
+func validateID(id string) error {
+	if id == "" {
+		return fmt.Errorf("config ID must not be empty")
+	}
+	for _, r := range id {
+		if !unicode.IsLetter(r) && !unicode.IsDigit(r) && r != '-' && r != '_' {
+			return fmt.Errorf("invalid character %q in config ID", r)
+		}
+	}
+	return nil
+}
+
+func (s *Store) filePath(k Kind, id string) string {
+	return filepath.Join(s.dirs[k], id+".json")
+}
+
+func (s *Store) backupPath(k Kind, id string, version int) string {
+	return filepath.Join(s.dirs[k], fmt.Sprintf("%s.v%d.json", id, version))
+}
+
+// isVersioned reports whether name matches <id>.v<number>.json.
+func isVersioned(name string) bool {
+	parts := strings.Split(name, ".")
+	if len(parts) != 3 || parts[2] != "json" {
+		return false
+	}
+	if !strings.HasPrefix(parts[1], "v") {
+		return false
+	}
+	_, err := strconv.Atoi(parts[1][1:])
+	return err == nil
+}
+
+func readHeader(data []byte) (header, error) {
+	var h header
+	if err := json.Unmarshal(data, &h); err != nil {
+		return header{}, err
+	}
+	return h, nil
+}
+
+// List returns metadata for every stored object of the given kind.
+func (s *Store) List(k Kind) ([]Meta, error) {
+	entries, err := os.ReadDir(s.dirs[k])
+	if err != nil {
+		return nil, err
+	}
+	out := []Meta{}
+	for _, e := range entries {
+		name := e.Name()
+		if e.IsDir() || !strings.HasSuffix(name, ".json") || isVersioned(name) {
+			continue
+		}
+		id := strings.TrimSuffix(name, ".json")
+		data, err := os.ReadFile(s.filePath(k, id))
+		if err != nil {
+			continue
+		}
+		h, err := readHeader(data)
+		if err != nil {
+			continue
+		}
+		out = append(out, Meta{ID: id, Name: h.Name, Version: h.Version})
+	}
+	return out, nil
+}
+
+// get returns the raw JSON bytes for the current revision.
+func (s *Store) get(k Kind, id string) ([]byte, error) {
+	if err := validateID(id); err != nil {
+		return nil, fmt.Errorf("%w: %v", ErrNotFound, err)
+	}
+	data, err := os.ReadFile(s.filePath(k, id))
+	if errors.Is(err, os.ErrNotExist) {
+		return nil, ErrNotFound
+	}
+	return data, err
+}
+
+// create writes a new object, deriving a unique ID from name when obj has none,
+// stamping version=1 and the given tag. It returns the raw stored bytes.
+func (s *Store) create(k Kind, obj map[string]any, tag string) (string, []byte, error) {
+	id, _ := obj["id"].(string)
+	if id == "" {
+		id = slugify(name(obj))
+	}
+	if err := validateID(id); err != nil {
+		return "", nil, err
+	}
+	if _, err := os.Stat(s.filePath(k, id)); err == nil {
+		id = id + "-" + strconv.FormatInt(time.Now().UnixMilli(), 10)
+	}
+	obj["id"] = id
+	obj["version"] = 1
+	if tag != "" {
+		obj["tag"] = tag
+	}
+	data, err := marshal(obj)
+	if err != nil {
+		return "", nil, err
+	}
+	return id, data, os.WriteFile(s.filePath(k, id), data, 0o644)
+}
+
+// update replaces the current revision, preserving the prior one as a backup
+// and incrementing the version. It returns the raw stored bytes.
+func (s *Store) update(k Kind, id string, obj map[string]any, tag string) ([]byte, error) {
+	if err := validateID(id); err != nil {
+		return nil, ErrNotFound
+	}
+	oldData, err := os.ReadFile(s.filePath(k, id))
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	oldHdr, err := readHeader(oldData)
+	if err != nil {
+		return nil, fmt.Errorf("parse existing JSON: %w", err)
+	}
+	if oldHdr.Version < 1 {
+		oldHdr.Version = 1
+	}
+	if err := os.WriteFile(s.backupPath(k, id, oldHdr.Version), oldData, 0o644); err != nil {
+		return nil, fmt.Errorf("create backup: %w", err)
+	}
+	obj["id"] = id
+	obj["version"] = oldHdr.Version + 1
+	if tag != "" {
+		obj["tag"] = tag
+	}
+	data, err := marshal(obj)
+	if err != nil {
+		return nil, err
+	}
+	return data, os.WriteFile(s.filePath(k, id), data, 0o644)
+}
+
+// Versions returns metadata for every persisted revision, newest-first.
+func (s *Store) Versions(k Kind, id string) ([]VersionMeta, error) {
+	if err := validateID(id); err != nil {
+		return nil, ErrNotFound
+	}
+	curInfo, err := os.Stat(s.filePath(k, id))
+	if errors.Is(err, os.ErrNotExist) {
+		return nil, ErrNotFound
+	} else if err != nil {
+		return nil, err
+	}
+	curData, err := os.ReadFile(s.filePath(k, id))
+	if err != nil {
+		return nil, err
+	}
+	curHdr, err := readHeader(curData)
+	if err != nil {
+		return nil, err
+	}
+	out := []VersionMeta{{
+		Version: curHdr.Version,
+		Name:    curHdr.Name,
+		Tag:     curHdr.Tag,
+		Current: true,
+		SavedAt: curInfo.ModTime(),
+	}}
+
+	entries, err := os.ReadDir(s.dirs[k])
+	if err != nil {
+		return nil, err
+	}
+	prefix := id + ".v"
+	for _, e := range entries {
+		name := e.Name()
+		if e.IsDir() || !strings.HasPrefix(name, prefix) || !isVersioned(name) {
+			continue
+		}
+		info, err := e.Info()
+		if err != nil {
+			continue
+		}
+		data, err := os.ReadFile(filepath.Join(s.dirs[k], name))
+		if err != nil {
+			continue
+		}
+		h, err := readHeader(data)
+		if err != nil {
+			continue
+		}
+		out = append(out, VersionMeta{
+			Version: h.Version,
+			Name:    h.Name,
+			Tag:     h.Tag,
+			SavedAt: info.ModTime(),
+		})
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Version > out[j].Version })
+	return out, nil
+}
+
+// getVersion returns the raw JSON bytes for a specific revision.
+func (s *Store) getVersion(k Kind, id string, version int) ([]byte, error) {
+	if err := validateID(id); err != nil {
+		return nil, ErrNotFound
+	}
+	curData, err := os.ReadFile(s.filePath(k, id))
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+	if h, err := readHeader(curData); err == nil && h.Version == version {
+		return curData, nil
+	}
+	data, err := os.ReadFile(s.backupPath(k, id, version))
+	if errors.Is(err, os.ErrNotExist) {
+		return nil, ErrNotFound
+	}
+	return data, err
+}
+
+// Promote re-saves a past revision as a new revision on top of history.
+func (s *Store) Promote(k Kind, id string, version int) error {
+	data, err := s.getVersion(k, id, version)
+	if err != nil {
+		return err
+	}
+	obj, err := unmarshal(data)
+	if err != nil {
+		return err
+	}
+	_, err = s.update(k, id, obj, fmt.Sprintf("restored from v%d", version))
+	return err
+}
+
+// Fork creates a brand-new object from a revision, with a fresh ID and version 1.
+func (s *Store) Fork(k Kind, id string, version int) (string, error) {
+	data, err := s.getVersion(k, id, version)
+	if err != nil {
+		return "", err
+	}
+	obj, err := unmarshal(data)
+	if err != nil {
+		return "", err
+	}
+	newID := id + "-fork-" + strconv.FormatInt(time.Now().UnixMilli(), 10)
+	obj["id"] = newID
+	obj["version"] = 1
+	delete(obj, "tag")
+	out, err := marshal(obj)
+	if err != nil {
+		return "", err
+	}
+	return newID, os.WriteFile(s.filePath(k, newID), out, 0o644)
+}
+
+// Delete moves an object and all its backups to a timestamped trash folder so
+// it can be recovered. Nothing is destroyed.
+func (s *Store) Delete(k Kind, id string) error {
+	if err := validateID(id); err != nil {
+		return ErrNotFound
+	}
+	if _, err := os.Stat(s.filePath(k, id)); err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return ErrNotFound
+		}
+		return err
+	}
+	trashDir := filepath.Join(s.rootDir, "trash", "configs", k.sub(), fmt.Sprintf("%s.%d", id, time.Now().UnixMilli()))
+	if err := os.MkdirAll(trashDir, 0o755); err != nil {
+		return fmt.Errorf("create trash dir: %w", err)
+	}
+	entries, err := os.ReadDir(s.dirs[k])
+	if err != nil {
+		return err
+	}
+	for _, e := range entries {
+		name := e.Name()
+		if e.IsDir() {
+			continue
+		}
+		if name == id+".json" || (strings.HasPrefix(name, id+".v") && isVersioned(name)) {
+			if err := os.Rename(filepath.Join(s.dirs[k], name), filepath.Join(trashDir, name)); err != nil {
+				return fmt.Errorf("move %s to trash: %w", name, err)
+			}
+		}
+	}
+	return nil
+}
+
+// ── typed wrappers ──────────────────────────────────────────────────────────
+
+// GetSet returns the current revision of a config set.
+func (s *Store) GetSet(id string) (ConfigSet, error) {
+	data, err := s.get(KindSet, id)
+	if err != nil {
+		return ConfigSet{}, err
+	}
+	var set ConfigSet
+	return set, json.Unmarshal(data, &set)
+}
+
+// GetSetVersion returns a specific revision of a config set.
+func (s *Store) GetSetVersion(id string, version int) (ConfigSet, error) {
+	data, err := s.getVersion(KindSet, id, version)
+	if err != nil {
+		return ConfigSet{}, err
+	}
+	var set ConfigSet
+	return set, json.Unmarshal(data, &set)
+}
+
+// CreateSet validates and stores a new config set, returning it with its
+// assigned ID and version.
+func (s *Store) CreateSet(set ConfigSet, tag string) (ConfigSet, error) {
+	if err := set.Validate(); err != nil {
+		return ConfigSet{}, err
+	}
+	obj, err := toMap(set)
+	if err != nil {
+		return ConfigSet{}, err
+	}
+	_, data, err := s.create(KindSet, obj, tag)
+	if err != nil {
+		return ConfigSet{}, err
+	}
+	var out ConfigSet
+	return out, json.Unmarshal(data, &out)
+}
+
+// UpdateSet validates and stores a new revision of an existing config set.
+func (s *Store) UpdateSet(id string, set ConfigSet, tag string) (ConfigSet, error) {
+	if err := set.Validate(); err != nil {
+		return ConfigSet{}, err
+	}
+	obj, err := toMap(set)
+	if err != nil {
+		return ConfigSet{}, err
+	}
+	data, err := s.update(KindSet, id, obj, tag)
+	if err != nil {
+		return ConfigSet{}, err
+	}
+	var out ConfigSet
+	return out, json.Unmarshal(data, &out)
+}
+
+// GetInstance returns the current revision of a config instance.
+func (s *Store) GetInstance(id string) (ConfigInstance, error) {
+	data, err := s.get(KindInstance, id)
+	if err != nil {
+		return ConfigInstance{}, err
+	}
+	var inst ConfigInstance
+	return inst, json.Unmarshal(data, &inst)
+}
+
+// GetInstanceVersion returns a specific revision of a config instance.
+func (s *Store) GetInstanceVersion(id string, version int) (ConfigInstance, error) {
+	data, err := s.getVersion(KindInstance, id, version)
+	if err != nil {
+		return ConfigInstance{}, err
+	}
+	var inst ConfigInstance
+	return inst, json.Unmarshal(data, &inst)
+}
+
+// setForInstance loads the schema an instance is bound to, honouring a pinned
+// SetVersion when set.
+func (s *Store) setForInstance(inst ConfigInstance) (ConfigSet, error) {
+	if inst.SetVersion > 0 {
+		return s.GetSetVersion(inst.SetID, inst.SetVersion)
+	}
+	return s.GetSet(inst.SetID)
+}
+
+// CreateInstance validates an instance against its set and stores it.
+func (s *Store) CreateInstance(inst ConfigInstance, tag string) (ConfigInstance, error) {
+	set, err := s.setForInstance(inst)
+	if err != nil {
+		return ConfigInstance{}, fmt.Errorf("load set %q: %w", inst.SetID, err)
+	}
+	if err := inst.ValidateAgainst(set); err != nil {
+		return ConfigInstance{}, err
+	}
+	obj, err := toMap(inst)
+	if err != nil {
+		return ConfigInstance{}, err
+	}
+	_, data, err := s.create(KindInstance, obj, tag)
+	if err != nil {
+		return ConfigInstance{}, err
+	}
+	var out ConfigInstance
+	return out, json.Unmarshal(data, &out)
+}
+
+// UpdateInstance validates and stores a new revision of an existing instance.
+func (s *Store) UpdateInstance(id string, inst ConfigInstance, tag string) (ConfigInstance, error) {
+	set, err := s.setForInstance(inst)
+	if err != nil {
+		return ConfigInstance{}, fmt.Errorf("load set %q: %w", inst.SetID, err)
+	}
+	if err := inst.ValidateAgainst(set); err != nil {
+		return ConfigInstance{}, err
+	}
+	obj, err := toMap(inst)
+	if err != nil {
+		return ConfigInstance{}, err
+	}
+	data, err := s.update(KindInstance, id, obj, tag)
+	if err != nil {
+		return ConfigInstance{}, err
+	}
+	var out ConfigInstance
+	return out, json.Unmarshal(data, &out)
+}
+
+// SetForInstance is the exported loader used by apply/diff callers.
+func (s *Store) SetForInstance(inst ConfigInstance) (ConfigSet, error) {
+	return s.setForInstance(inst)
+}
+
+// ── JSON helpers ────────────────────────────────────────────────────────────
+
+func name(obj map[string]any) string {
+	n, _ := obj["name"].(string)
+	return n
+}
+
+func marshal(obj map[string]any) ([]byte, error) {
+	return json.MarshalIndent(obj, "", "  ")
+}
+
+func unmarshal(data []byte) (map[string]any, error) {
+	var obj map[string]any
+	if err := json.Unmarshal(data, &obj); err != nil {
+		return nil, err
+	}
+	return obj, nil
+}
+
+// toMap round-trips a typed value through JSON into a generic map so the store
+// can stamp id/version/tag without knowing the concrete type.
+func toMap(v any) (map[string]any, error) {
+	data, err := json.Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+	return unmarshal(data)
+}
+
+// slugify converts a human-readable name into a URL-safe identifier.
+func slugify(s string) string {
+	var b strings.Builder
+	for _, r := range strings.ToLower(s) {
+		switch {
+		case r >= 'a' && r <= 'z', r >= '0' && r <= '9':
+			b.WriteRune(r)
+		default:
+			if b.Len() > 0 && b.String()[b.Len()-1] != '-' {
+				b.WriteByte('-')
+			}
+		}
+	}
+	result := strings.Trim(b.String(), "-")
+	if result == "" {
+		return "config"
+	}
+	return result
+}

internal/confmgr/store_test.go

@@ -0,0 +1,200 @@
+package confmgr
+
+import (
+	"testing"
+)
+
+func fptr(f float64) *float64 { return &f }
+
+func sampleSet() ConfigSet {
+	return ConfigSet{
+		Name:        "PSU",
+		Description: "power supply config",
+		Parameters: []Parameter{
+			{Key: "voltage", DS: "epics", Signal: "PSU:V", Type: TypeFloat, Default: 12.0, Mandatory: true, Min: fptr(0), Max: fptr(48)},
+			{Key: "enabled", DS: "epics", Signal: "PSU:EN", Type: TypeBool, Default: false},
+		},
+	}
+}
+
+func TestCreateAndGetSet(t *testing.T) {
+	s, err := New(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	out, err := s.CreateSet(sampleSet(), "initial")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out.ID == "" {
+		t.Fatal("expected generated ID")
+	}
+	if out.Version != 1 {
+		t.Errorf("version: want 1, got %d", out.Version)
+	}
+	got, err := s.GetSet(out.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.Name != "PSU" || len(got.Parameters) != 2 {
+		t.Errorf("round-trip mismatch: %+v", got)
+	}
+}
+
+func TestSetVersioning(t *testing.T) {
+	s, _ := New(t.TempDir())
+	created, _ := s.CreateSet(sampleSet(), "")
+	id := created.ID
+
+	// Update -> v2.
+	upd := sampleSet()
+	upd.Description = "edited"
+	v2, err := s.UpdateSet(id, upd, "edit")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if v2.Version != 2 {
+		t.Fatalf("version after update: want 2, got %d", v2.Version)
+	}
+
+	versions, err := s.Versions(KindSet, id)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(versions) != 2 {
+		t.Fatalf("want 2 versions, got %d", len(versions))
+	}
+	if !versions[0].Current || versions[0].Version != 2 {
+		t.Errorf("newest should be current v2: %+v", versions[0])
+	}
+
+	// Old version still retrievable.
+	old, err := s.GetSetVersion(id, 1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if old.Description != "power supply config" {
+		t.Errorf("v1 description changed: %q", old.Description)
+	}
+
+	// Promote v1 -> becomes v3 with original content.
+	if err := s.Promote(KindSet, id, 1); err != nil {
+		t.Fatal(err)
+	}
+	cur, _ := s.GetSet(id)
+	if cur.Version != 3 || cur.Description != "power supply config" {
+		t.Errorf("after promote: want v3 original desc, got v%d %q", cur.Version, cur.Description)
+	}
+}
+
+func TestForkSet(t *testing.T) {
+	s, _ := New(t.TempDir())
+	created, _ := s.CreateSet(sampleSet(), "")
+	_, _ = s.UpdateSet(created.ID, sampleSet(), "")
+
+	newID, err := s.Fork(KindSet, created.ID, 1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	forked, err := s.GetSet(newID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if forked.ID == created.ID {
+		t.Error("fork should have a new ID")
+	}
+	if forked.Version != 1 {
+		t.Errorf("fork version: want 1, got %d", forked.Version)
+	}
+	if forked.Tag != "" {
+		t.Errorf("fork tag should be cleared, got %q", forked.Tag)
+	}
+}
+
+func TestDeleteSetSoftDeletes(t *testing.T) {
+	s, _ := New(t.TempDir())
+	created, _ := s.CreateSet(sampleSet(), "")
+	if err := s.Delete(KindSet, created.ID); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := s.GetSet(created.ID); err == nil {
+		t.Error("expected set to be gone after delete")
+	}
+	// Deleting again is a not-found.
+	if err := s.Delete(KindSet, created.ID); err != ErrNotFound {
+		t.Errorf("want ErrNotFound, got %v", err)
+	}
+}
+
+func TestSetValidation(t *testing.T) {
+	s, _ := New(t.TempDir())
+	bad := ConfigSet{Name: "", Parameters: nil}
+	if _, err := s.CreateSet(bad, ""); err == nil {
+		t.Error("expected empty-name validation error")
+	}
+	dup := ConfigSet{Name: "x", Parameters: []Parameter{
+		{Key: "a", DS: "d", Signal: "s", Type: TypeFloat},
+		{Key: "a", DS: "d", Signal: "s2", Type: TypeFloat},
+	}}
+	if _, err := s.CreateSet(dup, ""); err == nil {
+		t.Error("expected duplicate-key validation error")
+	}
+	defaultOOR := ConfigSet{Name: "x", Parameters: []Parameter{
+		{Key: "a", DS: "d", Signal: "s", Type: TypeFloat, Default: 100.0, Max: fptr(10)},
+	}}
+	if _, err := s.CreateSet(defaultOOR, ""); err == nil {
+		t.Error("expected out-of-range default validation error")
+	}
+}
+
+func TestInstanceLifecycle(t *testing.T) {
+	s, _ := New(t.TempDir())
+	set, _ := s.CreateSet(sampleSet(), "")
+
+	inst := ConfigInstance{
+		Name:   "nominal",
+		SetID:  set.ID,
+		Values: map[string]any{"voltage": 24.0, "enabled": true},
+	}
+	out, err := s.CreateInstance(inst, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out.Version != 1 {
+		t.Errorf("instance version: want 1, got %d", out.Version)
+	}
+
+	// Update value -> v2.
+	out.Values["voltage"] = 36.0
+	v2, err := s.UpdateInstance(out.ID, out, "bump")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if v2.Version != 2 {
+		t.Errorf("instance version after update: want 2, got %d", v2.Version)
+	}
+}
+
+func TestInstanceValidation(t *testing.T) {
+	s, _ := New(t.TempDir())
+	set, _ := s.CreateSet(sampleSet(), "")
+
+	// voltage is mandatory with a default, so omitting it is OK; but an
+	// out-of-range value must fail.
+	bad := ConfigInstance{Name: "x", SetID: set.ID, Values: map[string]any{"voltage": 999.0}}
+	if _, err := s.CreateInstance(bad, ""); err == nil {
+		t.Error("expected out-of-range value error")
+	}
+
+	// Unknown parameter key must fail.
+	unknown := ConfigInstance{Name: "x", SetID: set.ID, Values: map[string]any{"nope": 1.0}}
+	if _, err := s.CreateInstance(unknown, ""); err == nil {
+		t.Error("expected unknown-parameter error")
+	}
+
+	// Unknown set must fail.
+	missing := ConfigInstance{Name: "x", SetID: "does-not-exist", Values: map[string]any{}}
+	if _, err := s.CreateInstance(missing, ""); err == nil {
+		t.Error("expected missing-set error")
+	}
+}

internal/datasource/synthetic/array_graph_test.go

@@ -0,0 +1,222 @@
+package synthetic
+
+import (
+	"context"
+	"log/slog"
+	"math"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/uopi/uopi/internal/broker"
+	"github.com/uopi/uopi/internal/datasource"
+	"github.com/uopi/uopi/internal/dsp"
+)
+
+// evalSampleDef compiles a SignalDef and evaluates it against per-source
+// Samples keyed by source node id, returning the output Sample.
+func evalSampleDef(t *testing.T, def SignalDef, srcVals map[string]dsp.Sample) dsp.Sample {
+	t.Helper()
+	rg, err := compileGraph(def)
+	if err != nil {
+		t.Fatalf("compileGraph: %v", err)
+	}
+	out, err := rg.evalSample(srcVals)
+	if err != nil {
+		t.Fatalf("evalSample: %v", err)
+	}
+	return out
+}
+
+// TestArrayElementwiseChain runs an array source through an elementwise op
+// (gain) and asserts the output stays an array, broadcast per element.
+func TestArrayElementwiseChain(t *testing.T) {
+	def := SignalDef{
+		Name: "scaled",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "source", DS: "x", Signal: "wave"},
+				{ID: "g", Kind: "op", Op: "gain", Inputs: []string{"a"}, Params: map[string]any{"gain": 2.0}},
+				{ID: "out", Kind: "output", Inputs: []string{"g"}},
+			},
+		},
+	}
+	out := evalSampleDef(t, def, map[string]dsp.Sample{"a": dsp.Array([]float64{1, 2, 3})})
+	if !out.IsArray {
+		t.Fatalf("want array output, got %v", out)
+	}
+	want := []float64{2, 4, 6}
+	for i, v := range want {
+		if out.Arr[i] != v {
+			t.Errorf("scaled[%d]: want %v, got %v", i, v, out.Arr[i])
+		}
+	}
+}
+
+// TestArrayReductionToScalar runs an array source into mean (array→scalar) and
+// asserts a scalar output and an array-output compile type for the producer.
+func TestArrayReductionToScalar(t *testing.T) {
+	def := SignalDef{
+		Name: "avg",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "source", DS: "x", Signal: "wave"},
+				{ID: "m", Kind: "op", Op: "mean", Inputs: []string{"a"}},
+				{ID: "out", Kind: "output", Inputs: []string{"m"}},
+			},
+		},
+	}
+	out := evalSampleDef(t, def, map[string]dsp.Sample{"a": dsp.Array([]float64{2, 4, 6, 8})})
+	if out.IsArray {
+		t.Fatalf("want scalar output, got array %v", out.Arr)
+	}
+	if math.Abs(out.F-5) > 1e-9 {
+		t.Errorf("mean: want 5, got %v", out.F)
+	}
+}
+
+// TestArrayOutTypeMetadata verifies compileGraph reports an array output type
+// for a pure-elementwise array graph and scalar for a reduction graph.
+func TestArrayOutTypeMetadata(t *testing.T) {
+	arrayGraph := SignalDef{
+		Name: "fftout",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "source", DS: "x", Signal: "wave"},
+				{ID: "f", Kind: "op", Op: "fft", Inputs: []string{"a"}},
+				{ID: "out", Kind: "output", Inputs: []string{"f"}},
+			},
+		},
+	}
+	rg, err := compileGraph(arrayGraph)
+	if err != nil {
+		t.Fatalf("compileGraph: %v", err)
+	}
+	if rg.outType != dsp.ValArray {
+		t.Errorf("fft graph outType: want ValArray, got %v", rg.outType)
+	}
+
+	reduction := SignalDef{
+		Name: "sumout",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "source", DS: "x", Signal: "wave"},
+				{ID: "s", Kind: "op", Op: "sum", Inputs: []string{"a"}},
+				{ID: "out", Kind: "output", Inputs: []string{"s"}},
+			},
+		},
+	}
+	rg2, err := compileGraph(reduction)
+	if err != nil {
+		t.Fatalf("compileGraph: %v", err)
+	}
+	if rg2.outType != dsp.ValScalar {
+		t.Errorf("sum graph outType: want ValScalar, got %v", rg2.outType)
+	}
+}
+
+// TestStatefulRejectsArray verifies a stateful op (moving_average) errors when
+// fed an array input at runtime.
+func TestStatefulRejectsArray(t *testing.T) {
+	def := SignalDef{
+		Name: "ma",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "source", DS: "x", Signal: "wave"},
+				{ID: "m", Kind: "op", Op: "moving_average", Inputs: []string{"a"}, Params: map[string]any{"window": 3.0}},
+				{ID: "out", Kind: "output", Inputs: []string{"m"}},
+			},
+		},
+	}
+	rg, err := compileGraph(def)
+	if err != nil {
+		t.Fatalf("compileGraph: %v", err)
+	}
+	if _, err := rg.evalSample(map[string]dsp.Sample{"a": dsp.Array([]float64{1, 2, 3})}); err == nil {
+		t.Error("expected moving_average to reject an array input")
+	}
+}
+
+// TestSubscribeArrayPassthrough is an end-to-end check that a synthetic with an
+// array-valued source and an elementwise op emits a []float64 over the broker,
+// and that GetMetadata reports the waveform type.
+func TestSubscribeArrayPassthrough(t *testing.T) {
+	log := slog.New(slog.NewTextHandler(os.Stderr, nil))
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	base := time.Date(2026, 6, 19, 10, 0, 0, 0, time.UTC)
+	src := &seqSource{name: "src", seq: []datasource.Value{
+		{Timestamp: base.Add(1 * time.Second), Data: []float64{1, 2, 3}, Quality: datasource.QualityGood},
+		{Timestamp: base.Add(2 * time.Second), Data: []float64{4, 5, 6}, Quality: datasource.QualityGood},
+	}}
+
+	brk := broker.New(ctx, log)
+	brk.Register(src)
+	syn := New(t.TempDir(), brk, log)
+	if err := syn.Connect(ctx); err != nil {
+		t.Fatal(err)
+	}
+	// gain x2 elementwise keeps the value an array.
+	if err := syn.AddSignal(SignalDef{
+		Name: "scaled",
+		Graph: &Graph{Output: "out", Nodes: []GraphNode{
+			{ID: "a", Kind: "source", DS: "src", Signal: "x"},
+			{ID: "g", Kind: "op", Op: "gain", Inputs: []string{"a"}, Params: map[string]any{"gain": 2.0}},
+			{ID: "out", Kind: "output", Inputs: []string{"g"}},
+		}},
+	}); err != nil {
+		t.Fatal(err)
+	}
+	// An fft-based signal has a statically-known array output type (the source's
+	// runtime type need not be known), so its metadata reports the waveform type.
+	if err := syn.AddSignal(SignalDef{
+		Name: "spectrum",
+		Graph: &Graph{Output: "out", Nodes: []GraphNode{
+			{ID: "a", Kind: "source", DS: "src", Signal: "x"},
+			{ID: "f", Kind: "op", Op: "fft", Inputs: []string{"a"}},
+			{ID: "out", Kind: "output", Inputs: []string{"f"}},
+		}},
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	meta, err := syn.GetMetadata(ctx, "spectrum")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if meta.Type != datasource.TypeFloat64Array {
+		t.Errorf("metadata type: want TypeFloat64Array, got %v", meta.Type)
+	}
+
+	ch := make(chan datasource.Value, 8)
+	if _, err := syn.Subscribe(ctx, "scaled", ch); err != nil {
+		t.Fatal(err)
+	}
+
+	want := [][]float64{{2, 4, 6}, {8, 10, 12}}
+	for i, w := range want {
+		select {
+		case v := <-ch:
+			arr, ok := v.Data.([]float64)
+			if !ok {
+				t.Fatalf("emit #%d: want []float64, got %T", i, v.Data)
+			}
+			if len(arr) != len(w) {
+				t.Fatalf("emit #%d: want len %d, got %d", i, len(w), len(arr))
+			}
+			for k, val := range w {
+				if arr[k] != val {
+					t.Errorf("emit #%d [%d]: want %v, got %v", i, k, val, arr[k])
+				}
+			}
+		case <-time.After(2 * time.Second):
+			t.Fatalf("timeout waiting for emit #%d", i)
+		}
+	}
+}

internal/datasource/synthetic/dsp_bridge.go

@@ -126,6 +126,30 @@ func buildNode(d NodeDef) (dsp.Node, error) {
 	case "lua":
 		return &dsp.LuaNode{Script: stringParam(p, "script"), Vars: stringSliceParam(p, "vars")}, nil
 
+	case "index":
+		return &dsp.IndexNode{I: int(floatParam(p, "i"))}, nil
+
+	case "slice":
+		return &dsp.SliceNode{Start: int(floatParam(p, "start")), End: int(floatParam(p, "end"))}, nil
+
+	case "sum":
+		return &dsp.SumNode{}, nil
+
+	case "mean":
+		return &dsp.MeanNode{}, nil
+
+	case "min":
+		return &dsp.MinNode{}, nil
+
+	case "max":
+		return &dsp.MaxNode{}, nil
+
+	case "length":
+		return &dsp.LengthNode{}, nil
+
+	case "fft":
+		return &dsp.FFTNode{}, nil
+
 	default:
 		return nil, fmt.Errorf("unknown node type %q", d.Type)
 	}

internal/datasource/synthetic/graph.go

@@ -13,9 +13,10 @@ import (
 // each node's inputs already resolved. Op-node state maps persist across
 // evaluations (for stateful nodes like moving_average / lua).
 type runtimeGraph struct {
-	order    []*rtNode  // topological order (sources first, output last)
-	sources  []rtSource // source nodes, in topological order
-	outputID string     // id of the output node
+	order    []*rtNode    // topological order (sources first, output last)
+	sources  []rtSource   // source nodes, in topological order
+	outputID string       // id of the output node
+	outType  dsp.ValType  // best-effort output type (scalar/array/unknown)
 }
 
 type rtNode struct {
@@ -41,24 +42,30 @@ func (rg *runtimeGraph) sourceRefs() []broker.SignalRef {
 	return refs
 }
 
-// eval computes the output value given the latest value for each source node
-// (keyed by source node id). Nodes are visited in topological order so every
-// input is already present in vals by the time a node is processed.
-func (rg *runtimeGraph) eval(sourceVals map[string]float64) (float64, error) {
-	vals := make(map[string]float64, len(rg.order))
+// evalSample computes the output Sample (scalar or array) given the latest
+// value for each source node (keyed by source node id). Nodes are visited in
+// topological order so every input is present by the time a node is processed.
+//
+// Op dispatch:
+//   - ArrayNode ops (reductions/producers) run natively on Samples.
+//   - stateless elementwise ops broadcast over array inputs.
+//   - stateful ops (filters) and lua are scalar-only; an array input errors,
+//     since their per-evaluation state cannot be split across array lanes.
+func (rg *runtimeGraph) evalSample(sourceVals map[string]dsp.Sample) (dsp.Sample, error) {
+	vals := make(map[string]dsp.Sample, len(rg.order))
 	for id, v := range sourceVals {
 		vals[id] = v
 	}
 	for _, n := range rg.order {
 		switch n.kind {
 		case "op":
-			in := make([]float64, len(n.inputs))
+			in := make([]dsp.Sample, len(n.inputs))
 			for i, id := range n.inputs {
 				in[i] = vals[id]
 			}
-			r, err := n.op.Process(in, n.state)
+			r, err := evalOp(n, in)
 			if err != nil {
-				return 0, fmt.Errorf("node %s (%s): %w", n.id, n.op.Type(), err)
+				return dsp.Sample{}, fmt.Errorf("node %s (%s): %w", n.id, n.op.Type(), err)
 			}
 			vals[n.id] = r
 		case "output":
@@ -70,6 +77,44 @@ func (rg *runtimeGraph) eval(sourceVals map[string]float64) (float64, error) {
 	return vals[rg.outputID], nil
 }
 
+// evalOp runs a single op node over its Sample inputs, choosing the right
+// execution path for the node type.
+func evalOp(n *rtNode, in []dsp.Sample) (dsp.Sample, error) {
+	if an, ok := n.op.(dsp.ArrayNode); ok {
+		return an.ProcessSample(in, n.state)
+	}
+	if dsp.StatelessElementwise(n.op.Type()) {
+		return dsp.ApplyElementwise(n.op, in, n.state)
+	}
+	// Stateful / lua: scalar-only.
+	row := make([]float64, len(in))
+	for i, s := range in {
+		if s.IsArray {
+			return dsp.Sample{}, fmt.Errorf("does not accept an array input")
+		}
+		row[i] = s.F
+	}
+	r, err := n.op.Process(row, n.state)
+	if err != nil {
+		return dsp.Sample{}, err
+	}
+	return dsp.Scalar(r), nil
+}
+
+// eval is the scalar wrapper around evalSample, kept so callers and tests that
+// deal purely in float64 (legacy linear graphs, scalar sources) are unchanged.
+func (rg *runtimeGraph) eval(sourceVals map[string]float64) (float64, error) {
+	sv := make(map[string]dsp.Sample, len(sourceVals))
+	for id, v := range sourceVals {
+		sv[id] = dsp.Scalar(v)
+	}
+	out, err := rg.evalSample(sv)
+	if err != nil {
+		return 0, err
+	}
+	return out.F, nil
+}
+
 // compileGraph converts a SignalDef into an executable runtimeGraph. When the
 // def carries an explicit Graph it is used directly; otherwise the legacy
 // Inputs+Pipeline form is converted to an equivalent linear graph (see toGraph).
@@ -83,23 +128,42 @@ func compileGraph(def SignalDef) (*runtimeGraph, error) {
 		return nil, err
 	}
 	rg := &runtimeGraph{outputID: g.Output}
+	// nodeType tracks each node's best-effort output type for static
+	// propagation. Sources are unknown at compile time (their real type is
+	// only known once data flows), so type errors here are advisory; runtime
+	// Sample typing is authoritative.
+	nodeType := make(map[string]dsp.ValType, len(order))
 	for _, gn := range order {
 		switch gn.Kind {
 		case "source":
 			rg.sources = append(rg.sources, rtSource{id: gn.ID, ref: broker.SignalRef{DS: gn.DS, Name: gn.Signal}})
+			nodeType[gn.ID] = dsp.ValUnknown
 		case "op":
 			node, err := buildNode(NodeDef{Type: gn.Op, Params: gn.Params})
 			if err != nil {
 				return nil, fmt.Errorf("node %q: %w", gn.ID, err)
 			}
+			inTypes := make([]dsp.ValType, len(gn.Inputs))
+			for i, id := range gn.Inputs {
+				inTypes[i] = nodeType[id]
+			}
+			ot, terr := dsp.OpOutputType(gn.Op, inTypes)
+			if terr != nil {
+				return nil, fmt.Errorf("node %q: %w", gn.ID, terr)
+			}
+			nodeType[gn.ID] = ot
 			rg.order = append(rg.order, &rtNode{id: gn.ID, kind: "op", op: node, state: map[string]any{}, inputs: gn.Inputs})
 		case "output":
 			rg.outputID = gn.ID
+			if len(gn.Inputs) > 0 {
+				nodeType[gn.ID] = nodeType[gn.Inputs[0]]
+			}
 			rg.order = append(rg.order, &rtNode{id: gn.ID, kind: "output", inputs: gn.Inputs})
 		default:
 			return nil, fmt.Errorf("node %q: unknown kind %q", gn.ID, gn.Kind)
 		}
 	}
+	rg.outType = nodeType[rg.outputID]
 	return rg, nil
 }
 

internal/datasource/synthetic/synthetic.go

@@ -13,6 +13,7 @@ import (
 
 	"github.com/uopi/uopi/internal/broker"
 	"github.com/uopi/uopi/internal/datasource"
+	"github.com/uopi/uopi/internal/dsp"
 )
 
 const definitionsFile = "synthetic.json"
@@ -78,7 +79,7 @@ func (s *Synthetic) ListSignals(_ context.Context) ([]datasource.Metadata, error
 
 	out := make([]datasource.Metadata, 0, len(s.signals))
 	for _, st := range s.signals {
-		out = append(out, defToMetadata(st.def))
+		out = append(out, defToMetadata(st.def, outTypeOf(st)))
 	}
 	return out, nil
 }
@@ -93,7 +94,7 @@ func (s *Synthetic) FilteredMetadata(keep func(SignalDef) bool) []datasource.Met
 	out := make([]datasource.Metadata, 0, len(s.signals))
 	for _, st := range s.signals {
 		if keep(st.def) {
-			out = append(out, defToMetadata(st.def))
+			out = append(out, defToMetadata(st.def, outTypeOf(st)))
 		}
 	}
 	return out
@@ -108,7 +109,7 @@ func (s *Synthetic) GetMetadata(_ context.Context, signal string) (datasource.Me
 	if !ok {
 		return datasource.Metadata{}, datasource.ErrNotFound
 	}
-	return defToMetadata(st.def), nil
+	return defToMetadata(st.def, outTypeOf(st)), nil
 }
 
 // Subscribe registers ch to receive computed values for the named signal.
@@ -138,7 +139,7 @@ func (s *Synthetic) Subscribe(ctx context.Context, signal string, ch chan<- data
 		defer cancel()
 
 		// Latest value and timestamp per source node id.
-		latest := make(map[string]float64, len(refs))
+		latest := make(map[string]dsp.Sample, len(refs))
 		latestTs := make([]time.Time, len(refs))
 		ready := make([]bool, len(refs))
 
@@ -163,7 +164,7 @@ func (s *Synthetic) Subscribe(ctx context.Context, signal string, ch chan<- data
 							if !ok {
 								return
 							}
-							val := toFloat64(u.Value.Data)
+							val := toSample(u.Value.Data)
 							select {
 							case updateCh <- indexedUpdate{idx: idx, val: val, ts: u.Value.Timestamp}:
 							default:
@@ -224,7 +225,7 @@ func (s *Synthetic) Subscribe(ctx context.Context, signal string, ch chan<- data
 					return
 				}
 
-				result, err := cur.rg.eval(latest)
+				result, err := cur.rg.evalSample(latest)
 				if err != nil {
 					s.log.Warn("synthetic: pipeline error", "signal", signal, "err", err)
 					continue
@@ -232,7 +233,7 @@ func (s *Synthetic) Subscribe(ctx context.Context, signal string, ch chan<- data
 
 				v := datasource.Value{
 					Timestamp: outTs,
-					Data:      result,
+					Data:      result.AsAny(),
 					Quality:   datasource.QualityGood,
 				}
 				select {
@@ -421,11 +422,17 @@ func (s *Synthetic) startSignal(def SignalDef) error {
 	return nil
 }
 
-// defToMetadata converts a SignalDef into a datasource.Metadata.
-func defToMetadata(def SignalDef) datasource.Metadata {
+// defToMetadata converts a SignalDef into a datasource.Metadata. outType is the
+// compiled graph's best-effort output type; an array output is reported as a
+// waveform (TypeFloat64Array) so widgets can pick a compatible view.
+func defToMetadata(def SignalDef, outType dsp.ValType) datasource.Metadata {
+	dt := datasource.TypeFloat64
+	if outType == dsp.ValArray {
+		dt = datasource.TypeFloat64Array
+	}
 	return datasource.Metadata{
 		Name:        def.Name,
-		Type:        datasource.TypeFloat64,
+		Type:        dt,
 		Unit:        def.Meta.Unit,
 		Description: def.Meta.Description,
 		DisplayLow:  def.Meta.DisplayLow,
@@ -434,7 +441,38 @@ func defToMetadata(def SignalDef) datasource.Metadata {
 	}
 }
 
-// toFloat64 coerces any numeric value from a datasource.Value.Data to float64.
+// outTypeOf returns the compiled output type for a signal state, or unknown.
+func outTypeOf(st *signalState) dsp.ValType {
+	if st == nil || st.rg == nil {
+		return dsp.ValUnknown
+	}
+	return st.rg.outType
+}
+
+// toSample coerces a datasource.Value.Data into a dsp.Sample: arrays become
+// array Samples (waveforms), everything else a scalar Sample.
+func toSample(v any) dsp.Sample {
+	switch val := v.(type) {
+	case []float64:
+		return dsp.Array(val)
+	case []float32:
+		out := make([]float64, len(val))
+		for i, e := range val {
+			out[i] = float64(e)
+		}
+		return dsp.Array(out)
+	case []int:
+		out := make([]float64, len(val))
+		for i, e := range val {
+			out[i] = float64(e)
+		}
+		return dsp.Array(out)
+	default:
+		return dsp.Scalar(toFloat64(v))
+	}
+}
+
+// toFloat64 coerces any numeric scalar value from a datasource.Value.Data to float64.
 func toFloat64(v any) float64 {
 	switch val := v.(type) {
 	case float64:
@@ -460,6 +498,6 @@ func toFloat64(v any) float64 {
 // indexedUpdate carries a value from one upstream goroutine to the pipeline runner.
 type indexedUpdate struct {
 	idx int
-	val float64
+	val dsp.Sample
 	ts  time.Time
 }

internal/dsp/array_nodes.go

@@ -0,0 +1,230 @@
+package dsp
+
+import (
+	"errors"
+	"fmt"
+	"math"
+)
+
+// This file holds ArrayNode ops: those that operate natively on waveform
+// (float64 array) Samples — reductions (array→scalar), producers (array→array),
+// and element access. Each also implements the legacy scalar Node interface
+// (treating a scalar as a single-element array) so it remains usable from the
+// scalar eval path.
+
+// reductionProcess adapts a scalar Process call to a reduction ArrayNode.
+func reductionProcess(n ArrayNode, in []float64, st map[string]any) (float64, error) {
+	s, err := n.ProcessSample(scalarInputs(in), st)
+	if err != nil {
+		return 0, err
+	}
+	return s.F, nil
+}
+
+// ── IndexNode ───────────────────────────────────────────────────────────────
+
+// IndexNode extracts element I of an array input (array→scalar).
+type IndexNode struct{ I int }
+
+func (n *IndexNode) Type() string { return "index" }
+func (n *IndexNode) Process(in []float64, st map[string]any) (float64, error) {
+	return reductionProcess(n, in, st)
+}
+func (n *IndexNode) ProcessSample(in []Sample, _ map[string]any) (Sample, error) {
+	if len(in) == 0 {
+		return Sample{}, errors.New("index: no inputs")
+	}
+	arr := in[0].AsArray()
+	if n.I < 0 || n.I >= len(arr) {
+		return Sample{}, fmt.Errorf("index: %d out of range [0,%d)", n.I, len(arr))
+	}
+	return Scalar(arr[n.I]), nil
+}
+
+// ── SliceNode ───────────────────────────────────────────────────────────────
+
+// SliceNode returns a sub-range [Start,End) of an array input (array→array),
+// clamped to the array bounds. End <= 0 means "to the end".
+type SliceNode struct{ Start, End int }
+
+func (n *SliceNode) Type() string { return "slice" }
+func (n *SliceNode) Process(in []float64, st map[string]any) (float64, error) {
+	s, err := n.ProcessSample(scalarInputs(in), st)
+	if err != nil {
+		return 0, err
+	}
+	if len(s.Arr) == 0 {
+		return 0, nil
+	}
+	return s.Arr[0], nil
+}
+func (n *SliceNode) ProcessSample(in []Sample, _ map[string]any) (Sample, error) {
+	if len(in) == 0 {
+		return Sample{}, errors.New("slice: no inputs")
+	}
+	arr := in[0].AsArray()
+	start := n.Start
+	if start < 0 {
+		start = 0
+	}
+	if start > len(arr) {
+		start = len(arr)
+	}
+	end := n.End
+	if end <= 0 || end > len(arr) {
+		end = len(arr)
+	}
+	if end < start {
+		end = start
+	}
+	out := make([]float64, end-start)
+	copy(out, arr[start:end])
+	return Array(out), nil
+}
+
+// ── reductions ────────────────────────────────────────────────────────────────
+
+// SumNode sums an array input (array→scalar).
+type SumNode struct{}
+
+func (n *SumNode) Type() string { return "sum" }
+func (n *SumNode) Process(in []float64, st map[string]any) (float64, error) {
+	return reductionProcess(n, in, st)
+}
+func (n *SumNode) ProcessSample(in []Sample, _ map[string]any) (Sample, error) {
+	if len(in) == 0 {
+		return Sample{}, errors.New("sum: no inputs")
+	}
+	var s float64
+	for _, v := range in[0].AsArray() {
+		s += v
+	}
+	return Scalar(s), nil
+}
+
+// MeanNode averages an array input (array→scalar).
+type MeanNode struct{}
+
+func (n *MeanNode) Type() string { return "mean" }
+func (n *MeanNode) Process(in []float64, st map[string]any) (float64, error) {
+	return reductionProcess(n, in, st)
+}
+func (n *MeanNode) ProcessSample(in []Sample, _ map[string]any) (Sample, error) {
+	if len(in) == 0 {
+		return Sample{}, errors.New("mean: no inputs")
+	}
+	arr := in[0].AsArray()
+	if len(arr) == 0 {
+		return Scalar(0), nil
+	}
+	var s float64
+	for _, v := range arr {
+		s += v
+	}
+	return Scalar(s / float64(len(arr))), nil
+}
+
+// MinNode returns the minimum element of an array input (array→scalar).
+type MinNode struct{}
+
+func (n *MinNode) Type() string { return "min" }
+func (n *MinNode) Process(in []float64, st map[string]any) (float64, error) {
+	return reductionProcess(n, in, st)
+}
+func (n *MinNode) ProcessSample(in []Sample, _ map[string]any) (Sample, error) {
+	if len(in) == 0 {
+		return Sample{}, errors.New("min: no inputs")
+	}
+	arr := in[0].AsArray()
+	if len(arr) == 0 {
+		return Scalar(0), nil
+	}
+	m := arr[0]
+	for _, v := range arr[1:] {
+		if v < m {
+			m = v
+		}
+	}
+	return Scalar(m), nil
+}
+
+// MaxNode returns the maximum element of an array input (array→scalar).
+type MaxNode struct{}
+
+func (n *MaxNode) Type() string { return "max" }
+func (n *MaxNode) Process(in []float64, st map[string]any) (float64, error) {
+	return reductionProcess(n, in, st)
+}
+func (n *MaxNode) ProcessSample(in []Sample, _ map[string]any) (Sample, error) {
+	if len(in) == 0 {
+		return Sample{}, errors.New("max: no inputs")
+	}
+	arr := in[0].AsArray()
+	if len(arr) == 0 {
+		return Scalar(0), nil
+	}
+	m := arr[0]
+	for _, v := range arr[1:] {
+		if v > m {
+			m = v
+		}
+	}
+	return Scalar(m), nil
+}
+
+// LengthNode returns the element count of an array input (array→scalar).
+type LengthNode struct{}
+
+func (n *LengthNode) Type() string { return "length" }
+func (n *LengthNode) Process(in []float64, st map[string]any) (float64, error) {
+	return reductionProcess(n, in, st)
+}
+func (n *LengthNode) ProcessSample(in []Sample, _ map[string]any) (Sample, error) {
+	if len(in) == 0 {
+		return Sample{}, errors.New("length: no inputs")
+	}
+	return Scalar(float64(len(in[0].AsArray()))), nil
+}
+
+// ── FFTNode ────────────────────────────────────────────────────────────────
+
+// FFTNode computes the magnitude spectrum of an array input (array→array). The
+// input is zero-padded to the next power of two; the output has that length and
+// holds |X[k]| for each frequency bin.
+type FFTNode struct{}
+
+func (n *FFTNode) Type() string { return "fft" }
+func (n *FFTNode) Process(in []float64, st map[string]any) (float64, error) {
+	s, err := n.ProcessSample(scalarInputs(in), st)
+	if err != nil {
+		return 0, err
+	}
+	if len(s.Arr) == 0 {
+		return 0, nil
+	}
+	return s.Arr[0], nil
+}
+func (n *FFTNode) ProcessSample(in []Sample, _ map[string]any) (Sample, error) {
+	if len(in) == 0 {
+		return Sample{}, errors.New("fft: no inputs")
+	}
+	return Array(fftMagnitude(in[0].AsArray())), nil
+}
+
+// fftMagnitude returns the magnitude spectrum of x, zero-padded to the next
+// power of two. Returns an empty slice for empty input.
+func fftMagnitude(x []float64) []float64 {
+	if len(x) == 0 {
+		return nil
+	}
+	n := nextPow2(len(x))
+	re := make([]float64, n)
+	im := make([]float64, n)
+	copy(re, x)
+	fftRadix2(re, im)
+	mag := make([]float64, n)
+	for i := range mag {
+		mag[i] = math.Hypot(re[i], im[i])
+	}
+	return mag
+}

internal/dsp/array_nodes_test.go

@@ -0,0 +1,213 @@
+package dsp
+
+import (
+	"math"
+	"testing"
+)
+
+func TestSampleRoundTrip(t *testing.T) {
+	s := Scalar(3.5)
+	if s.IsArray {
+		t.Error("Scalar should not be an array")
+	}
+	if s.Type() != ValScalar {
+		t.Errorf("Scalar type: want ValScalar, got %v", s.Type())
+	}
+	if s.AsAny() != 3.5 {
+		t.Errorf("Scalar AsAny: want 3.5, got %v", s.AsAny())
+	}
+	if got := s.AsArray(); len(got) != 1 || got[0] != 3.5 {
+		t.Errorf("Scalar AsArray: want [3.5], got %v", got)
+	}
+
+	a := Array([]float64{1, 2, 3})
+	if !a.IsArray {
+		t.Error("Array should be an array")
+	}
+	if a.Type() != ValArray {
+		t.Errorf("Array type: want ValArray, got %v", a.Type())
+	}
+	got, ok := a.AsAny().([]float64)
+	if !ok || len(got) != 3 {
+		t.Errorf("Array AsAny: want []float64 len 3, got %v", a.AsAny())
+	}
+}
+
+func TestApplyElementwiseAllScalar(t *testing.T) {
+	n := &AddNode{}
+	out, err := ApplyElementwise(n, []Sample{Scalar(2), Scalar(3)}, map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out.IsArray || out.F != 5 {
+		t.Errorf("all-scalar add: want scalar 5, got %v", out)
+	}
+}
+
+func TestApplyElementwiseBroadcast(t *testing.T) {
+	// array ⊕ scalar: scalar is a constant broadcast across the array.
+	n := &AddNode{}
+	out, err := ApplyElementwise(n, []Sample{Array([]float64{1, 2, 3}), Scalar(10)}, map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !out.IsArray {
+		t.Fatalf("array+scalar: want array, got %v", out)
+	}
+	want := []float64{11, 12, 13}
+	for i, v := range want {
+		if out.Arr[i] != v {
+			t.Errorf("array+scalar[%d]: want %v, got %v", i, v, out.Arr[i])
+		}
+	}
+}
+
+func TestApplyElementwiseArrayArray(t *testing.T) {
+	n := &MultiplyNode{}
+	out, err := ApplyElementwise(n, []Sample{Array([]float64{1, 2, 3}), Array([]float64{4, 5, 6})}, map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []float64{4, 10, 18}
+	for i, v := range want {
+		if out.Arr[i] != v {
+			t.Errorf("array*array[%d]: want %v, got %v", i, v, out.Arr[i])
+		}
+	}
+}
+
+func TestApplyElementwiseLengthMismatch(t *testing.T) {
+	n := &AddNode{}
+	_, err := ApplyElementwise(n, []Sample{Array([]float64{1, 2}), Array([]float64{1, 2, 3})}, map[string]any{})
+	if err == nil {
+		t.Error("expected length-mismatch error")
+	}
+}
+
+func TestReductionNodes(t *testing.T) {
+	arr := []Sample{Array([]float64{2, 4, 6, 8})}
+	cases := []struct {
+		name string
+		node ArrayNode
+		want float64
+	}{
+		{"sum", &SumNode{}, 20},
+		{"mean", &MeanNode{}, 5},
+		{"min", &MinNode{}, 2},
+		{"max", &MaxNode{}, 8},
+		{"length", &LengthNode{}, 4},
+		{"index", &IndexNode{I: 2}, 6},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			out, err := tc.node.ProcessSample(arr, map[string]any{})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if out.IsArray || out.F != tc.want {
+				t.Errorf("%s: want scalar %v, got %v", tc.name, tc.want, out)
+			}
+		})
+	}
+}
+
+func TestIndexNodeOutOfRange(t *testing.T) {
+	n := &IndexNode{I: 9}
+	_, err := n.ProcessSample([]Sample{Array([]float64{1, 2, 3})}, map[string]any{})
+	if err == nil {
+		t.Error("expected out-of-range error")
+	}
+}
+
+func TestSliceNode(t *testing.T) {
+	n := &SliceNode{Start: 1, End: 3}
+	out, err := n.ProcessSample([]Sample{Array([]float64{10, 20, 30, 40})}, map[string]any{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []float64{20, 30}
+	if len(out.Arr) != len(want) {
+		t.Fatalf("slice: want len %d, got %d", len(want), len(out.Arr))
+	}
+	for i, v := range want {
+		if out.Arr[i] != v {
+			t.Errorf("slice[%d]: want %v, got %v", i, v, out.Arr[i])
+		}
+	}
+}
+
+func TestFFTMagnitude(t *testing.T) {
+	// A constant signal has all energy in bin 0 (the DC term equals the sum).
+	x := []float64{1, 1, 1, 1}
+	mag := fftMagnitude(x)
+	if len(mag) != 4 {
+		t.Fatalf("fft len: want 4, got %d", len(mag))
+	}
+	if math.Abs(mag[0]-4) > 1e-9 {
+		t.Errorf("fft DC bin: want 4, got %v", mag[0])
+	}
+	for k := 1; k < len(mag); k++ {
+		if math.Abs(mag[k]) > 1e-9 {
+			t.Errorf("fft bin %d: want ~0, got %v", k, mag[k])
+		}
+	}
+}
+
+func TestFFTSingleTone(t *testing.T) {
+	// One full cycle of a cosine over 8 samples → energy in bins 1 and N-1.
+	n := 8
+	x := make([]float64, n)
+	for i := range x {
+		x[i] = math.Cos(2 * math.Pi * float64(i) / float64(n))
+	}
+	mag := fftMagnitude(x)
+	if math.Abs(mag[1]-float64(n)/2) > 1e-6 {
+		t.Errorf("fft tone bin 1: want %v, got %v", float64(n)/2, mag[1])
+	}
+	if math.Abs(mag[n-1]-float64(n)/2) > 1e-6 {
+		t.Errorf("fft tone bin %d: want %v, got %v", n-1, float64(n)/2, mag[n-1])
+	}
+}
+
+func TestOpOutputType(t *testing.T) {
+	cases := []struct {
+		op      string
+		in      []ValType
+		want    ValType
+		wantErr bool
+	}{
+		// reductions → scalar regardless of input
+		{"sum", []ValType{ValArray}, ValScalar, false},
+		{"mean", []ValType{ValScalar}, ValScalar, false},
+		{"index", []ValType{ValUnknown}, ValScalar, false},
+		// array producers require array, yield array
+		{"fft", []ValType{ValArray}, ValArray, false},
+		{"slice", []ValType{ValUnknown}, ValArray, false},
+		{"fft", []ValType{ValScalar}, ValUnknown, true},
+		// scalar-only reject arrays
+		{"moving_average", []ValType{ValScalar}, ValScalar, false},
+		{"lua", []ValType{ValArray}, ValUnknown, true},
+		{"rms", []ValType{ValUnknown}, ValScalar, false},
+		// elementwise: array if any array, scalar if all scalar, else unknown
+		{"add", []ValType{ValScalar, ValScalar}, ValScalar, false},
+		{"add", []ValType{ValArray, ValScalar}, ValArray, false},
+		{"gain", []ValType{ValUnknown}, ValUnknown, false},
+		{"expr", []ValType{ValArray, ValScalar}, ValArray, false},
+	}
+	for _, tc := range cases {
+		got, err := OpOutputType(tc.op, tc.in)
+		if tc.wantErr {
+			if err == nil {
+				t.Errorf("OpOutputType(%q,%v): expected error", tc.op, tc.in)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("OpOutputType(%q,%v): unexpected error %v", tc.op, tc.in, err)
+			continue
+		}
+		if got != tc.want {
+			t.Errorf("OpOutputType(%q,%v): want %v, got %v", tc.op, tc.in, tc.want, got)
+		}
+	}
+}

internal/dsp/fft.go

@@ -0,0 +1,58 @@
+package dsp
+
+import "math"
+
+// nextPow2 returns the smallest power of two >= n (and at least 1).
+func nextPow2(n int) int {
+	p := 1
+	for p < n {
+		p <<= 1
+	}
+	return p
+}
+
+// fftRadix2 computes the in-place iterative radix-2 Cooley-Tukey FFT of the
+// complex signal held in re/im. len(re) == len(im) must be a power of two. The
+// transform overwrites re/im with the frequency-domain result. This is a small
+// self-contained implementation (no external dependency) used by the synthetic
+// fft op.
+func fftRadix2(re, im []float64) {
+	n := len(re)
+	if n <= 1 {
+		return
+	}
+
+	// Bit-reversal permutation.
+	for i, j := 1, 0; i < n; i++ {
+		bit := n >> 1
+		for ; j&bit != 0; bit >>= 1 {
+			j ^= bit
+		}
+		j ^= bit
+		if i < j {
+			re[i], re[j] = re[j], re[i]
+			im[i], im[j] = im[j], im[i]
+		}
+	}
+
+	// Danielson-Lanczos butterflies.
+	for length := 2; length <= n; length <<= 1 {
+		ang := -2 * math.Pi / float64(length)
+		wReal, wImag := math.Cos(ang), math.Sin(ang)
+		for i := 0; i < n; i += length {
+			curReal, curImag := 1.0, 0.0
+			half := length >> 1
+			for k := 0; k < half; k++ {
+				a := i + k
+				b := i + k + half
+				tReal := curReal*re[b] - curImag*im[b]
+				tImag := curReal*im[b] + curImag*re[b]
+				re[b] = re[a] - tReal
+				im[b] = im[a] - tImag
+				re[a] += tReal
+				im[a] += tImag
+				curReal, curImag = curReal*wReal-curImag*wImag, curReal*wImag+curImag*wReal
+			}
+		}
+	}
+}

internal/dsp/sample.go

@@ -0,0 +1,151 @@
+package dsp
+
+import "fmt"
+
+// ValType is the data type of a Sample: a scalar float, a float array
+// (waveform), or — at graph-compile time, before a source's real type is
+// known — unknown.
+type ValType uint8
+
+const (
+	ValUnknown ValType = iota
+	ValScalar
+	ValArray
+)
+
+func (t ValType) String() string {
+	switch t {
+	case ValScalar:
+		return "scalar"
+	case ValArray:
+		return "array"
+	default:
+		return "unknown"
+	}
+}
+
+// Sample is a value flowing through the synthetic DSP graph: either a scalar
+// float64 or a float64 array (waveform). It is the array-aware counterpart of
+// the bare float64 the legacy scalar Node interface uses.
+type Sample struct {
+	F       float64
+	Arr     []float64
+	IsArray bool
+}
+
+// Scalar wraps a float64 as a scalar Sample.
+func Scalar(f float64) Sample { return Sample{F: f} }
+
+// Array wraps a []float64 as an array Sample.
+func Array(a []float64) Sample { return Sample{Arr: a, IsArray: true} }
+
+// Type reports whether the sample is a scalar or an array.
+func (s Sample) Type() ValType {
+	if s.IsArray {
+		return ValArray
+	}
+	return ValScalar
+}
+
+// AsAny returns the value in the form datasource.Value.Data expects: a
+// []float64 for arrays, a float64 for scalars.
+func (s Sample) AsAny() any {
+	if s.IsArray {
+		return s.Arr
+	}
+	return s.F
+}
+
+// AsArray returns the sample's data as a slice: the array itself, or a
+// single-element slice for a scalar. Used by reductions that accept either.
+func (s Sample) AsArray() []float64 {
+	if s.IsArray {
+		return s.Arr
+	}
+	return []float64{s.F}
+}
+
+// ArrayNode is an optional extension of Node implemented by ops that operate
+// natively on Samples (reductions array→scalar, producers array→array, etc.).
+// eval prefers ProcessSample when a node implements it.
+type ArrayNode interface {
+	Node
+	ProcessSample(inputs []Sample, state map[string]any) (Sample, error)
+}
+
+// statelessElementwise lists scalar ops that are safe to broadcast element-wise
+// over array inputs: they hold no per-evaluation state, so running the legacy
+// Process once per array lane is well-defined. Stateful ops (moving_average,
+// rms, lowpass, derivative, integrate) and lua are excluded — a single shared
+// state map cannot be meaningfully split across lanes.
+var statelessElementwise = map[string]bool{
+	"gain": true, "offset": true, "add": true, "subtract": true,
+	"multiply": true, "divide": true, "clamp": true, "threshold": true,
+	"expr": true,
+}
+
+// StatelessElementwise reports whether a scalar op type may be broadcast over
+// array inputs via ApplyElementwise.
+func StatelessElementwise(nodeType string) bool { return statelessElementwise[nodeType] }
+
+// scalarInputs wraps a legacy float64 input slice as scalar Samples.
+func scalarInputs(in []float64) []Sample {
+	out := make([]Sample, len(in))
+	for i, v := range in {
+		out[i] = Scalar(v)
+	}
+	return out
+}
+
+// ApplyElementwise runs a stateless scalar Node over Sample inputs. If every
+// input is scalar it calls Process once and wraps the result. If any input is
+// an array it broadcasts: scalar inputs act as constants, all array inputs must
+// share a common length (else an error), and Process is invoked once per index.
+//
+// The node MUST be stateless (see StatelessElementwise) — a shared state map
+// cannot be split across array lanes.
+func ApplyElementwise(n Node, inputs []Sample, state map[string]any) (Sample, error) {
+	// Determine the array length, if any input is an array.
+	length := -1
+	for _, s := range inputs {
+		if !s.IsArray {
+			continue
+		}
+		if length == -1 {
+			length = len(s.Arr)
+		} else if len(s.Arr) != length {
+			return Sample{}, fmt.Errorf("%s: array length mismatch (%d vs %d)", n.Type(), length, len(s.Arr))
+		}
+	}
+
+	if length == -1 {
+		// All scalar — single legacy call.
+		row := make([]float64, len(inputs))
+		for i, s := range inputs {
+			row[i] = s.F
+		}
+		r, err := n.Process(row, state)
+		if err != nil {
+			return Sample{}, err
+		}
+		return Scalar(r), nil
+	}
+
+	out := make([]float64, length)
+	row := make([]float64, len(inputs))
+	for i := 0; i < length; i++ {
+		for j, s := range inputs {
+			if s.IsArray {
+				row[j] = s.Arr[i]
+			} else {
+				row[j] = s.F
+			}
+		}
+		r, err := n.Process(row, state)
+		if err != nil {
+			return Sample{}, err
+		}
+		out[i] = r
+	}
+	return Array(out), nil
+}

internal/dsp/types.go

@@ -0,0 +1,74 @@
+package dsp
+
+import "fmt"
+
+// Op type categories for static (compile-time / editor) type propagation.
+// These mirror the runtime dispatch in the synthetic graph evaluator and the
+// frontend's inferNodeTypes (web/src/lib/synthTypes.ts) — keep the three in
+// sync; a parity test guards the Go/TS pair.
+var (
+	// reductionOps collapse an array (or scalar) to a single scalar.
+	reductionOps = map[string]bool{
+		"index": true, "length": true, "sum": true,
+		"mean": true, "min": true, "max": true,
+	}
+	// arrayProducerOps require an array input and yield an array.
+	arrayProducerOps = map[string]bool{
+		"fft": true, "slice": true,
+	}
+	// scalarOnlyOps reject array inputs and yield a scalar. Stateful filters
+	// plus lua (whose state/closure cannot be broadcast per array lane).
+	scalarOnlyOps = map[string]bool{
+		"moving_average": true, "rms": true, "lowpass": true,
+		"derivative": true, "integrate": true, "lua": true,
+	}
+)
+
+// OpOutputType reports the output ValType of an op given its input types, and
+// an error if the inputs are definitely incompatible with the op. Inputs may be
+// ValUnknown (a source whose real type is not yet known at compile time); such
+// inputs never trigger an error — runtime Sample typing is authoritative.
+func OpOutputType(op string, in []ValType) (ValType, error) {
+	switch {
+	case reductionOps[op]:
+		return ValScalar, nil
+
+	case arrayProducerOps[op]:
+		for _, t := range in {
+			if t == ValScalar {
+				return ValUnknown, fmt.Errorf("%s requires an array input", op)
+			}
+		}
+		return ValArray, nil
+
+	case scalarOnlyOps[op]:
+		for _, t := range in {
+			if t == ValArray {
+				return ValUnknown, fmt.Errorf("%s does not accept an array input", op)
+			}
+		}
+		return ValScalar, nil
+
+	default:
+		// Elementwise stateless ops (gain, offset, add, subtract, multiply,
+		// divide, clamp, threshold, expr): array if any input is an array,
+		// scalar if all inputs are definitely scalar, otherwise unknown.
+		anyArray, anyUnknown := false, false
+		for _, t := range in {
+			switch t {
+			case ValArray:
+				anyArray = true
+			case ValUnknown:
+				anyUnknown = true
+			}
+		}
+		switch {
+		case anyArray:
+			return ValArray, nil
+		case anyUnknown:
+			return ValUnknown, nil
+		default:
+			return ValScalar, nil
+		}
+	}
+}

internal/server/server.go

@@ -12,6 +12,7 @@ import (
 	"github.com/uopi/uopi/internal/api"
 	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
+	"github.com/uopi/uopi/internal/confmgr"
 	"github.com/uopi/uopi/internal/controllogic"
 	"github.com/uopi/uopi/internal/datasource/synthetic"
 	"github.com/uopi/uopi/internal/metrics"
@@ -28,7 +29,7 @@ type Server struct {
 
 // New creates the HTTP server, registers all routes, and returns a ready-to-start Server.
 // synth may be nil if the synthetic data source is not enabled.
-func New(addr string, webFS fs.FS, brk *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, policy *access.Policy, acl *panelacl.Store, ctrlLogic *controllogic.Store, ctrlEngine *controllogic.Engine, dialogs *DialogHub, rec audit.Recorder, channelFinderURL, archiverURL, trustedUserHeader string, log *slog.Logger) *Server {
+func New(addr string, webFS fs.FS, brk *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, cfgStore *confmgr.Store, policy *access.Policy, acl *panelacl.Store, ctrlLogic *controllogic.Store, ctrlEngine *controllogic.Engine, dialogs *DialogHub, rec audit.Recorder, channelFinderURL, archiverURL, trustedUserHeader string, log *slog.Logger) *Server {
 	if rec == nil {
 		rec = audit.Nop()
 	}
@@ -49,7 +50,7 @@ func New(addr string, webFS fs.FS, brk *broker.Broker, synth *synthetic.Syntheti
 	// REST API — registered on a dedicated mux so it can be wrapped with the
 	// access-control middleware (identity resolution + global level enforcement).
 	apiMux := http.NewServeMux()
-	api.New(brk, synth, store, policy, acl, ctrlLogic, ctrlEngine, rec, channelFinderURL, archiverURL, log).Register(apiMux, apiPrefix)
+	api.New(brk, synth, store, cfgStore, policy, acl, ctrlLogic, ctrlEngine, rec, channelFinderURL, archiverURL, log).Register(apiMux, apiPrefix)
 	mux.Handle(apiPrefix+"/", accessMiddleware(policy, trustedUserHeader, apiMux))
 
 	// Embedded frontend — must be last (catch-all)

web/src/Canvas.tsx

@@ -155,7 +155,7 @@ export default function Canvas({ iface, onNavigate, timeRange }: Props) {
 
   return (
     <div class="canvas-container">
-      <div class="canvas-area" style={`width:${iface.w}px;height:${iface.h}px;`}>
+      <div class="canvas-area canvas-view-bare" style={`width:${iface.w}px;height:${iface.h}px;`}>
         {iface.widgets.map(widget => {
           const Comp = COMPONENTS[widget.type];
           const inner = Comp

web/src/ConfigManager.tsx

@@ -0,0 +1,816 @@
+import { h, Fragment } from 'preact';
+import { useState, useEffect, useCallback } from 'preact/hooks';
+import SignalPicker, { SignalOption } from './SignalPicker';
+
+// ── Types (mirror internal/confmgr) ──────────────────────────────────────────
+
+type ParamType = 'float64' | 'int64' | 'bool' | 'string' | 'enum';
+
+interface Parameter {
+  key: string;
+  label?: string;
+  group?: string;
+  subgroup?: string;
+  ds: string;
+  signal: string;
+  type: ParamType;
+  default?: any;
+  mandatory?: boolean;
+  min?: number;
+  max?: number;
+  enumValues?: string[];
+  unit?: string;
+  description?: string;
+}
+
+interface ConfigSet {
+  id: string;
+  name: string;
+  description?: string;
+  version: number;
+  tag?: string;
+  owner?: string;
+  parameters: Parameter[];
+}
+
+interface ConfigInstance {
+  id: string;
+  name: string;
+  setId: string;
+  setVersion?: number;
+  version: number;
+  tag?: string;
+  owner?: string;
+  values: Record<string, any>;
+}
+
+interface Meta { id: string; name: string; version: number; }
+interface VersionMeta { version: number; name: string; tag?: string; current: boolean; savedAt: string; }
+
+interface ApplyEntry { key: string; ds: string; signal: string; value?: any; ok: boolean; skipped?: boolean; error?: string; }
+interface ApplyResult { instanceId: string; setId: string; entries: ApplyEntry[]; applied: number; failed: number; skipped: number; }
+
+type DiffStatus = 'added' | 'removed' | 'changed' | 'unchanged';
+interface SetDiffEntry { key: string; status: DiffStatus; left?: Parameter; right?: Parameter; }
+interface InstanceDiffEntry { key: string; status: DiffStatus; left?: any; right?: any; }
+
+const PARAM_TYPES: ParamType[] = ['float64', 'int64', 'bool', 'string', 'enum'];
+
+// ── API helper ───────────────────────────────────────────────────────────────
+
+async function apiJSON<T = any>(url: string, opts?: RequestInit): Promise<T | null> {
+  const res = await fetch(url, opts);
+  if (!res.ok && res.status !== 204) {
+    let msg = `HTTP ${res.status}`;
+    try { const e = await res.json(); if (e && e.error) msg = e.error; } catch { /* ignore */ }
+    throw new Error(msg);
+  }
+  if (res.status === 204) return null;
+  return res.json();
+}
+
+// Lazily-loaded data-source + signal options powering the SignalPicker.
+function useSignals() {
+  const [dataSources, setDataSources] = useState<string[]>([]);
+  const [dsSignals, setDsSignals] = useState<Record<string, string[]>>({});
+
+  useEffect(() => {
+    fetch('/api/v1/datasources')
+      .then(r => (r.ok ? r.json() : []))
+      .then((ds: { name: string }[]) => setDataSources(ds.map(d => d.name)))
+      .catch(() => {});
+  }, []);
+
+  const loadSignals = useCallback((ds: string) => {
+    if (!ds) return;
+    setDsSignals(prev => {
+      if (prev[ds]) return prev;
+      fetch(`/api/v1/signals?ds=${encodeURIComponent(ds)}`)
+        .then(r => (r.ok ? r.json() : []))
+        .then((sigs: { name: string }[]) => setDsSignals(p => ({ ...p, [ds]: sigs.map(s => s.name) })))
+        .catch(() => {});
+      return prev;
+    });
+  }, []);
+
+  function allOptions(): SignalOption[] {
+    const out: SignalOption[] = [];
+    for (const ds of dataSources) for (const name of dsSignals[ds] ?? []) out.push({ ds, name });
+    return out;
+  }
+  function openAll() { dataSources.forEach(loadSignals); }
+
+  return { allOptions, openAll };
+}
+
+function splitRef(ref: string): { ds: string; signal: string } {
+  const i = ref.indexOf(':');
+  if (i < 0) return { ds: '', signal: ref };
+  return { ds: ref.slice(0, i), signal: ref.slice(i + 1) };
+}
+
+function fmtTime(iso: string): string {
+  const d = new Date(iso);
+  if (isNaN(d.getTime())) return iso;
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}`;
+}
+
+// ── Top-level modal ───────────────────────────────────────────────────────────
+
+interface Props { onClose: () => void; }
+
+export default function ConfigManager({ onClose }: Props) {
+  const [tab, setTab] = useState<'sets' | 'instances'>('sets');
+
+  return (
+    <div class="cl-overlay" onMouseDown={(e) => { if (e.target === e.currentTarget) onClose(); }}>
+      <div class="cl-modal">
+        <header class="cl-header">
+          <span class="cl-title">Configuration manager</span>
+          <span class="hint cl-subtitle">Versioned configuration sets (schemas) and instances (values) that apply to signals.</span>
+          <div class="cl-header-actions">
+            <button class="panel-btn" onClick={onClose}>Close</button>
+          </div>
+        </header>
+
+        <div class="cfg-tabs">
+          <button class={`cfg-tab${tab === 'sets' ? ' cfg-tab-active' : ''}`} onClick={() => setTab('sets')}>Sets</button>
+          <button class={`cfg-tab${tab === 'instances' ? ' cfg-tab-active' : ''}`} onClick={() => setTab('instances')}>Instances</button>
+        </div>
+
+        {tab === 'sets' ? <SetsManager /> : <InstancesManager />}
+      </div>
+    </div>
+  );
+}
+
+// ── Sets manager ──────────────────────────────────────────────────────────────
+
+function SetsManager() {
+  const [sets, setSets] = useState<Meta[]>([]);
+  const [selectedId, setSelectedId] = useState<string | null>(null);
+  const [working, setWorking] = useState<ConfigSet | null>(null);
+  const [dirty, setDirty] = useState(false);
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [diff, setDiff] = useState<{ title: string; entries: SetDiffEntry[] } | null>(null);
+  const { allOptions, openAll } = useSignals();
+
+  const reload = useCallback(async () => {
+    try { setSets((await apiJSON<Meta[]>('/api/v1/config/sets')) ?? []); }
+    catch (err) { setError(`Failed to load sets: ${msg(err)}`); }
+  }, []);
+  useEffect(() => { reload(); }, [reload]);
+
+  async function select(id: string) {
+    if (dirty && !confirm('Discard unsaved changes?')) return;
+    setError(null);
+    try {
+      const s = await apiJSON<ConfigSet>(`/api/v1/config/sets/${encodeURIComponent(id)}`);
+      setSelectedId(id);
+      setWorking(s);
+      setDirty(false);
+    } catch (err) { setError(msg(err)); }
+  }
+
+  async function createSet() {
+    setBusy(true); setError(null);
+    try {
+      const body = { name: 'New config set', description: '', parameters: [] };
+      const created = await apiJSON<ConfigSet>('/api/v1/config/sets', jsonPost(body));
+      await reload();
+      setSelectedId(created!.id);
+      setWorking(created);
+      setDirty(false);
+    } catch (err) { setError(`Create failed: ${msg(err)}`); }
+    finally { setBusy(false); }
+  }
+
+  async function save() {
+    if (!working) return;
+    setBusy(true); setError(null);
+    try {
+      const saved = await apiJSON<ConfigSet>(`/api/v1/config/sets/${encodeURIComponent(working.id)}`, jsonPut(working));
+      setWorking(saved);
+      setDirty(false);
+      await reload();
+    } catch (err) { setError(`Save failed: ${msg(err)}`); }
+    finally { setBusy(false); }
+  }
+
+  async function remove(id: string) {
+    if (!confirm('Delete this config set? A server-side copy is kept in trash.')) return;
+    setBusy(true); setError(null);
+    try {
+      await apiJSON(`/api/v1/config/sets/${encodeURIComponent(id)}`, { method: 'DELETE' });
+      if (selectedId === id) { setSelectedId(null); setWorking(null); setDirty(false); }
+      await reload();
+    } catch (err) { setError(`Delete failed: ${msg(err)}`); }
+    finally { setBusy(false); }
+  }
+
+  function patch(p: Partial<ConfigSet>) {
+    if (!working) return;
+    setWorking({ ...working, ...p });
+    setDirty(true);
+  }
+  function patchParam(i: number, p: Partial<Parameter>) {
+    if (!working) return;
+    const params = working.parameters.map((x, idx) => (idx === i ? { ...x, ...p } : x));
+    patch({ parameters: params });
+  }
+  function addParam() {
+    if (!working) return;
+    const n = working.parameters.length + 1;
+    patch({ parameters: [...working.parameters, { key: `param${n}`, ds: '', signal: '', type: 'float64' }] });
+  }
+  function removeParam(i: number) {
+    if (!working) return;
+    patch({ parameters: working.parameters.filter((_, idx) => idx !== i) });
+  }
+
+  async function showDiff(av: number, bv: number) {
+    if (!working) return;
+    setError(null);
+    try {
+      const q = new URLSearchParams({ a: working.id, av: String(av), b: working.id, bv: String(bv) });
+      const entries = (await apiJSON<SetDiffEntry[]>(`/api/v1/config/sets/diff?${q}`)) ?? [];
+      setDiff({ title: `${working.name}: v${av} → v${bv}`, entries });
+    } catch (err) { setError(`Diff failed: ${msg(err)}`); }
+  }
+
+  return (
+    <div class="cl-body">
+      <div class="cl-list">
+        <div class="cl-list-head">
+          <span>Config sets</span>
+          <button class="panel-btn" disabled={busy} onClick={createSet}>+ New</button>
+        </div>
+        {sets.length === 0 && <div class="hint cl-list-empty">No config sets yet.</div>}
+        {sets.map(s => (
+          <div key={s.id} class={`cl-list-item${selectedId === s.id ? ' cl-list-item-active' : ''}`} onClick={() => select(s.id)}>
+            <span class="cl-list-name" title={s.name}>{s.name || '(unnamed)'}</span>
+            <span class="cfg-badge" title="Current version">v{s.version}</span>
+            <button class="cl-mini-btn" title="Delete" onClick={(e) => { e.stopPropagation(); remove(s.id); }}>✕</button>
+          </div>
+        ))}
+      </div>
+
+      <div class="cl-editor-wrap">
+        {error && <div class="cl-error">{error}</div>}
+        {!working && <div class="cl-empty hint">Select a config set on the left, or create a new one.</div>}
+        {working && (
+          <div class="cfg-editor">
+            <div class="cfg-edit-bar">
+              <input class="prop-input cl-name-input" value={working.name} placeholder="Set name"
+                onInput={(e) => patch({ name: (e.target as HTMLInputElement).value })} />
+              <span class="cfg-badge">v{working.version}</span>
+              {dirty && <span class="cl-dirty">unsaved</span>}
+              <button class="panel-btn panel-btn-primary" disabled={busy || !dirty} onClick={save}>Save</button>
+            </div>
+            <input class="prop-input" value={working.description ?? ''} placeholder="Description (optional)"
+              onInput={(e) => patch({ description: (e.target as HTMLInputElement).value })} />
+
+            <div class="cfg-section-head">
+              <span>Parameters</span>
+              <button class="panel-btn" onClick={addParam}>+ Add parameter</button>
+            </div>
+            {working.parameters.length === 0 && <div class="hint">No parameters. Each parameter binds a target signal with a default and constraints.</div>}
+            <div class="cfg-params">
+              {working.parameters.map((p, i) => (
+                <ParamEditor key={i} param={p} allOptions={allOptions()} onOpenSignals={openAll}
+                  onChange={(patch2) => patchParam(i, patch2)} onRemove={() => removeParam(i)} />
+              ))}
+            </div>
+
+            <VersionPanel kind="sets" id={working.id} onReload={reload}
+              onForked={(id) => { reload(); select(id); }}
+              onPromoted={() => select(working.id)}
+              onCompare={showDiff} onError={setError} />
+          </div>
+        )}
+      </div>
+
+      {diff && <DiffModal title={diff.title} onClose={() => setDiff(null)}>
+        <SetDiffTable entries={diff.entries} />
+      </DiffModal>}
+    </div>
+  );
+}
+
+function ParamEditor({ param, allOptions, onOpenSignals, onChange, onRemove }: {
+  param: Parameter;
+  allOptions: SignalOption[];
+  onOpenSignals: () => void;
+  onChange: (p: Partial<Parameter>) => void;
+  onRemove: () => void;
+}) {
+  const ref = param.ds || param.signal ? `${param.ds}:${param.signal}` : '';
+  const isNum = param.type === 'float64' || param.type === 'int64';
+  return (
+    <div class="cfg-param">
+      <div class="cfg-param-row">
+        <div class="cfg-field cfg-field-key">
+          <label>Key</label>
+          <input class="prop-input" value={param.key} onInput={(e) => onChange({ key: (e.target as HTMLInputElement).value })} />
+        </div>
+        <div class="cfg-field cfg-field-label">
+          <label>Label</label>
+          <input class="prop-input" value={param.label ?? ''} placeholder="(optional)"
+            onInput={(e) => onChange({ label: (e.target as HTMLInputElement).value })} />
+        </div>
+        <div class="cfg-field cfg-field-type">
+          <label>Type</label>
+          <select class="prop-select" value={param.type} onChange={(e) => onChange({ type: (e.target as HTMLSelectElement).value as ParamType })}>
+            {PARAM_TYPES.map(t => <option key={t} value={t}>{t}</option>)}
+          </select>
+        </div>
+        <button class="cl-mini-btn cfg-param-del" title="Remove parameter" onClick={onRemove}>✕</button>
+      </div>
+
+      <div class="cfg-param-row">
+        <div class="cfg-field cfg-field-target">
+          <label>Target signal</label>
+          <SignalPicker value={ref} options={allOptions} onOpen={onOpenSignals} allowFreeform
+            onChange={(r) => { const s = splitRef(r); onChange({ ds: s.ds, signal: s.signal }); }} />
+        </div>
+        <div class="cfg-field cfg-field-default">
+          <label>Default</label>
+          {param.type === 'bool' ? (
+            <select class="prop-select" value={String(param.default ?? '')}
+              onChange={(e) => { const v = (e.target as HTMLSelectElement).value; onChange({ default: v === '' ? undefined : v === 'true' }); }}>
+              <option value="">(none)</option>
+              <option value="true">true</option>
+              <option value="false">false</option>
+            </select>
+          ) : (
+            <input class="prop-input" type={isNum ? 'number' : 'text'} value={param.default ?? ''}
+              onInput={(e) => onChange({ default: coerceVal((e.target as HTMLInputElement).value, param.type) })} />
+          )}
+        </div>
+        <label class="cfg-mandatory">
+          <input type="checkbox" checked={!!param.mandatory} onChange={(e) => onChange({ mandatory: (e.target as HTMLInputElement).checked })} />
+          Mandatory
+        </label>
+      </div>
+
+      <div class="cfg-param-row">
+        <div class="cfg-field">
+          <label>Group</label>
+          <input class="prop-input" value={param.group ?? ''} placeholder="(optional)"
+            onInput={(e) => onChange({ group: (e.target as HTMLInputElement).value })} />
+        </div>
+        <div class="cfg-field">
+          <label>Unit</label>
+          <input class="prop-input" value={param.unit ?? ''} placeholder="(optional)"
+            onInput={(e) => onChange({ unit: (e.target as HTMLInputElement).value })} />
+        </div>
+        {isNum && (
+          <Fragment>
+            <div class="cfg-field cfg-field-num">
+              <label>Min</label>
+              <input class="prop-input" type="number" value={param.min ?? ''}
+                onInput={(e) => onChange({ min: numOrUndef((e.target as HTMLInputElement).value) })} />
+            </div>
+            <div class="cfg-field cfg-field-num">
+              <label>Max</label>
+              <input class="prop-input" type="number" value={param.max ?? ''}
+                onInput={(e) => onChange({ max: numOrUndef((e.target as HTMLInputElement).value) })} />
+            </div>
+          </Fragment>
+        )}
+        {param.type === 'enum' && (
+          <div class="cfg-field cfg-field-enum">
+            <label>Enum values (comma-separated)</label>
+            <input class="prop-input" value={(param.enumValues ?? []).join(', ')} placeholder="a, b, c"
+              onInput={(e) => onChange({ enumValues: (e.target as HTMLInputElement).value.split(',').map(s => s.trim()).filter(Boolean) })} />
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}
+
+// ── Instances manager ─────────────────────────────────────────────────────────
+
+function InstancesManager() {
+  const [instances, setInstances] = useState<Meta[]>([]);
+  const [sets, setSets] = useState<Meta[]>([]);
+  const [selectedId, setSelectedId] = useState<string | null>(null);
+  const [working, setWorking] = useState<ConfigInstance | null>(null);
+  const [boundSet, setBoundSet] = useState<ConfigSet | null>(null);
+  const [dirty, setDirty] = useState(false);
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [applyResult, setApplyResult] = useState<ApplyResult | null>(null);
+  const [diff, setDiff] = useState<{ title: string; entries: InstanceDiffEntry[] } | null>(null);
+  const [showNew, setShowNew] = useState(false);
+
+  const reload = useCallback(async () => {
+    try {
+      setInstances((await apiJSON<Meta[]>('/api/v1/config/instances')) ?? []);
+      setSets((await apiJSON<Meta[]>('/api/v1/config/sets')) ?? []);
+    } catch (err) { setError(`Failed to load: ${msg(err)}`); }
+  }, []);
+  useEffect(() => { reload(); }, [reload]);
+
+  async function loadSet(setId: string, setVersion?: number): Promise<ConfigSet | null> {
+    const path = setVersion && setVersion > 0
+      ? `/api/v1/config/sets/${encodeURIComponent(setId)}/versions/${setVersion}`
+      : `/api/v1/config/sets/${encodeURIComponent(setId)}`;
+    return apiJSON<ConfigSet>(path);
+  }
+
+  async function select(id: string) {
+    if (dirty && !confirm('Discard unsaved changes?')) return;
+    setError(null); setApplyResult(null);
+    try {
+      const inst = await apiJSON<ConfigInstance>(`/api/v1/config/instances/${encodeURIComponent(id)}`);
+      const set = await loadSet(inst!.setId, inst!.setVersion);
+      setSelectedId(id);
+      setWorking(inst);
+      setBoundSet(set);
+      setDirty(false);
+    } catch (err) { setError(msg(err)); }
+  }
+
+  async function createInstance(name: string, setId: string) {
+    setBusy(true); setError(null);
+    try {
+      const body = { name, setId, values: {} };
+      const created = await apiJSON<ConfigInstance>('/api/v1/config/instances', jsonPost(body));
+      const set = await loadSet(created!.setId, created!.setVersion);
+      await reload();
+      setSelectedId(created!.id);
+      setWorking(created);
+      setBoundSet(set);
+      setDirty(false);
+      setShowNew(false);
+    } catch (err) { setError(`Create failed: ${msg(err)}`); }
+    finally { setBusy(false); }
+  }
+
+  async function save() {
+    if (!working) return;
+    setBusy(true); setError(null);
+    try {
+      const saved = await apiJSON<ConfigInstance>(`/api/v1/config/instances/${encodeURIComponent(working.id)}`, jsonPut(working));
+      setWorking(saved);
+      setDirty(false);
+      await reload();
+    } catch (err) { setError(`Save failed: ${msg(err)}`); }
+    finally { setBusy(false); }
+  }
+
+  async function remove(id: string) {
+    if (!confirm('Delete this config instance? A server-side copy is kept in trash.')) return;
+    setBusy(true); setError(null);
+    try {
+      await apiJSON(`/api/v1/config/instances/${encodeURIComponent(id)}`, { method: 'DELETE' });
+      if (selectedId === id) { setSelectedId(null); setWorking(null); setBoundSet(null); setDirty(false); }
+      await reload();
+    } catch (err) { setError(`Delete failed: ${msg(err)}`); }
+    finally { setBusy(false); }
+  }
+
+  async function apply() {
+    if (!working) return;
+    if (!confirm('Apply this configuration? Each value is written to its target signal.')) return;
+    setBusy(true); setError(null); setApplyResult(null);
+    try {
+      const res = await apiJSON<ApplyResult>(`/api/v1/config/instances/${encodeURIComponent(working.id)}/apply`, { method: 'POST' });
+      setApplyResult(res);
+    } catch (err) { setError(`Apply failed: ${msg(err)}`); }
+    finally { setBusy(false); }
+  }
+
+  function setValue(key: string, value: any) {
+    if (!working) return;
+    const values = { ...working.values };
+    if (value === undefined) delete values[key];
+    else values[key] = value;
+    setWorking({ ...working, values });
+    setDirty(true);
+  }
+
+  async function showDiff(av: number, bv: number) {
+    if (!working) return;
+    setError(null);
+    try {
+      const q = new URLSearchParams({ a: working.id, av: String(av), b: working.id, bv: String(bv) });
+      const entries = (await apiJSON<InstanceDiffEntry[]>(`/api/v1/config/instances/diff?${q}`)) ?? [];
+      setDiff({ title: `${working.name}: v${av} → v${bv}`, entries });
+    } catch (err) { setError(`Diff failed: ${msg(err)}`); }
+  }
+
+  const setName = (id: string) => sets.find(s => s.id === id)?.name ?? id;
+
+  return (
+    <div class="cl-body">
+      <div class="cl-list">
+        <div class="cl-list-head">
+          <span>Instances</span>
+          <button class="panel-btn" disabled={busy || sets.length === 0} onClick={() => setShowNew(true)}>+ New</button>
+        </div>
+        {sets.length === 0 && <div class="hint cl-list-empty">Create a config set first.</div>}
+        {sets.length > 0 && instances.length === 0 && <div class="hint cl-list-empty">No instances yet.</div>}
+        {instances.map(s => (
+          <div key={s.id} class={`cl-list-item${selectedId === s.id ? ' cl-list-item-active' : ''}`} onClick={() => select(s.id)}>
+            <span class="cl-list-name" title={s.name}>{s.name || '(unnamed)'}</span>
+            <span class="cfg-badge">v{s.version}</span>
+            <button class="cl-mini-btn" title="Delete" onClick={(e) => { e.stopPropagation(); remove(s.id); }}>✕</button>
+          </div>
+        ))}
+      </div>
+
+      <div class="cl-editor-wrap">
+        {error && <div class="cl-error">{error}</div>}
+        {!working && <div class="cl-empty hint">Select an instance on the left, or create a new one.</div>}
+        {working && (
+          <div class="cfg-editor">
+            <div class="cfg-edit-bar">
+              <input class="prop-input cl-name-input" value={working.name} placeholder="Instance name"
+                onInput={(e) => { setWorking({ ...working, name: (e.target as HTMLInputElement).value }); setDirty(true); }} />
+              <span class="cfg-badge">v{working.version}</span>
+              {dirty && <span class="cl-dirty">unsaved</span>}
+              <button class="panel-btn panel-btn-primary" disabled={busy || !dirty} onClick={save}>Save</button>
+              <button class="panel-btn" disabled={busy || dirty} title={dirty ? 'Save before applying' : 'Write values to signals'} onClick={apply}>Apply</button>
+            </div>
+            <div class="hint">Based on set <b>{setName(working.setId)}</b>{working.setVersion ? ` (v${working.setVersion})` : ''}.</div>
+
+            {!boundSet && <div class="cl-error">Bound set could not be loaded.</div>}
+            {boundSet && (
+              <div class="cfg-values">
+                {boundSet.parameters.length === 0 && <div class="hint">The bound set has no parameters.</div>}
+                {boundSet.parameters.map(p => (
+                  <ValueRow key={p.key} param={p} value={working.values[p.key]} onChange={(v) => setValue(p.key, v)} />
+                ))}
+              </div>
+            )}
+
+            {applyResult && <ApplyResultView result={applyResult} />}
+
+            <VersionPanel kind="instances" id={working.id} onReload={reload}
+              onForked={(id) => { reload(); select(id); }}
+              onPromoted={() => select(working.id)}
+              onCompare={showDiff} onError={setError} />
+          </div>
+        )}
+      </div>
+
+      {showNew && <NewInstanceDialog sets={sets} busy={busy} onCancel={() => setShowNew(false)} onCreate={createInstance} />}
+
+      {diff && <DiffModal title={diff.title} onClose={() => setDiff(null)}>
+        <InstanceDiffTable entries={diff.entries} />
+      </DiffModal>}
+    </div>
+  );
+}
+
+function ValueRow({ param, value, onChange }: { param: Parameter; value: any; onChange: (v: any) => void }) {
+  const label = param.label || param.key;
+  const isNum = param.type === 'float64' || param.type === 'int64';
+  const defText = param.default !== undefined && param.default !== null ? String(param.default) : '';
+  return (
+    <div class="cfg-value-row">
+      <div class="cfg-value-label">
+        {param.mandatory && <span class="cfg-req" title="Mandatory">*</span>}
+        <span title={`${param.ds}:${param.signal}`}>{label}</span>
+        {param.unit && <span class="hint cfg-unit">{param.unit}</span>}
+      </div>
+      <div class="cfg-value-input">
+        {param.type === 'bool' ? (
+          <select class="prop-select" value={value === undefined ? '' : String(value)}
+            onChange={(e) => { const v = (e.target as HTMLSelectElement).value; onChange(v === '' ? undefined : v === 'true'); }}>
+            <option value="">{defText ? `default (${defText})` : '(unset)'}</option>
+            <option value="true">true</option>
+            <option value="false">false</option>
+          </select>
+        ) : param.type === 'enum' ? (
+          <select class="prop-select" value={value === undefined ? '' : String(value)}
+            onChange={(e) => { const v = (e.target as HTMLSelectElement).value; onChange(v === '' ? undefined : v); }}>
+            <option value="">{defText ? `default (${defText})` : '(unset)'}</option>
+            {(param.enumValues ?? []).map(ev => <option key={ev} value={ev}>{ev}</option>)}
+          </select>
+        ) : (
+          <input class="prop-input" type={isNum ? 'number' : 'text'}
+            value={value === undefined ? '' : value}
+            placeholder={defText ? `default: ${defText}` : '(unset)'}
+            onInput={(e) => { const raw = (e.target as HTMLInputElement).value; onChange(raw === '' ? undefined : coerceVal(raw, param.type)); }} />
+        )}
+      </div>
+      <span class="cfg-value-target hint" title="Target signal">{param.ds}:{param.signal}</span>
+    </div>
+  );
+}
+
+function NewInstanceDialog({ sets, busy, onCancel, onCreate }: {
+  sets: Meta[]; busy: boolean; onCancel: () => void; onCreate: (name: string, setId: string) => void;
+}) {
+  const [name, setName] = useState('New instance');
+  const [setId, setSetId] = useState(sets[0]?.id ?? '');
+  return (
+    <div class="cl-confirm-overlay" onMouseDown={(e) => { if (e.target === e.currentTarget) onCancel(); }}>
+      <div class="cl-confirm">
+        <div class="cl-confirm-title">New config instance</div>
+        <div class="cfg-field">
+          <label>Name</label>
+          <input class="prop-input" value={name} autoFocus onInput={(e) => setName((e.target as HTMLInputElement).value)} />
+        </div>
+        <div class="cfg-field">
+          <label>Config set</label>
+          <select class="prop-select" value={setId} onChange={(e) => setSetId((e.target as HTMLSelectElement).value)}>
+            {sets.map(s => <option key={s.id} value={s.id}>{s.name} (v{s.version})</option>)}
+          </select>
+        </div>
+        <div class="cl-confirm-actions">
+          <button class="panel-btn" onClick={onCancel}>Cancel</button>
+          <button class="panel-btn panel-btn-primary" disabled={busy || !setId || !name.trim()}
+            onClick={() => onCreate(name.trim(), setId)}>Create</button>
+        </div>
+      </div>
+    </div>
+  );
+}
+
+function ApplyResultView({ result }: { result: ApplyResult }) {
+  return (
+    <div class="cfg-apply-result">
+      <div class="cfg-apply-head">
+        Applied <b>{result.applied}</b>, failed <b class={result.failed ? 'cfg-fail' : ''}>{result.failed}</b>, skipped <b>{result.skipped}</b>
+      </div>
+      <table class="cfg-apply-table">
+        <thead><tr><th>Parameter</th><th>Target</th><th>Value</th><th>Result</th></tr></thead>
+        <tbody>
+          {result.entries.map(e => (
+            <tr key={e.key}>
+              <td>{e.key}</td>
+              <td class="hint">{e.ds}:{e.signal}</td>
+              <td>{e.value !== undefined ? String(e.value) : '—'}</td>
+              <td>
+                {e.skipped ? <span class="hint">skipped</span>
+                  : e.ok ? <span class="cfg-ok">ok</span>
+                  : <span class="cfg-fail" title={e.error}>failed</span>}
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
+}
+
+// ── Versions panel (shared) ───────────────────────────────────────────────────
+
+function VersionPanel({ kind, id, onForked, onPromoted, onCompare, onError }: {
+  kind: 'sets' | 'instances';
+  id: string;
+  onReload: () => void;
+  onForked: (newId: string) => void;
+  onPromoted: () => void;
+  onCompare: (av: number, bv: number) => void;
+  onError: (m: string) => void;
+}) {
+  const [versions, setVersions] = useState<VersionMeta[]>([]);
+  const [open, setOpen] = useState(false);
+  const [a, setA] = useState<number | null>(null);
+  const [b, setB] = useState<number | null>(null);
+
+  const base = `/api/v1/config/${kind}`;
+
+  const load = useCallback(async () => {
+    try {
+      const v = (await apiJSON<VersionMeta[]>(`${base}/${encodeURIComponent(id)}/versions`)) ?? [];
+      setVersions(v);
+      if (v.length >= 2) { setA(v[1].version); setB(v[0].version); }
+      else if (v.length === 1) { setA(v[0].version); setB(v[0].version); }
+    } catch (err) { onError(`Versions failed: ${msg(err)}`); }
+  }, [base, id, onError]);
+
+  useEffect(() => { if (open) load(); }, [open, load]);
+  // Reset when switching object.
+  useEffect(() => { setOpen(false); setVersions([]); }, [id]);
+
+  async function fork(version: number) {
+    try {
+      const obj = await apiJSON<{ id: string }>(`${base}/${encodeURIComponent(id)}/versions/${version}/fork`, { method: 'POST' });
+      onForked(obj!.id);
+    } catch (err) { onError(`Fork failed: ${msg(err)}`); }
+  }
+  async function promote(version: number) {
+    if (!confirm(`Promote v${version} to a new current version?`)) return;
+    try {
+      await apiJSON(`${base}/${encodeURIComponent(id)}/versions/${version}/promote`, { method: 'POST' });
+      onPromoted();
+    } catch (err) { onError(`Promote failed: ${msg(err)}`); }
+  }
+
+  return (
+    <div class="cfg-versions">
+      <button class="cfg-versions-toggle" onClick={() => setOpen(o => !o)}>
+        {open ? '▾' : '▸'} Version history
+      </button>
+      {open && (
+        <div class="cfg-versions-body">
+          {versions.length === 0 && <div class="hint">No versions.</div>}
+          {versions.map(v => (
+            <div key={v.version} class={`cfg-version-row${v.current ? ' cfg-version-current' : ''}`}>
+              <span class="cfg-version-num">v{v.version}{v.current && <span class="cfg-badge">current</span>}</span>
+              <span class="cfg-version-tag hint" title={v.tag}>{v.tag || ''}</span>
+              <span class="cfg-version-time hint">{fmtTime(v.savedAt)}</span>
+              <button class="cl-mini-btn" title="Fork into a new object" onClick={() => fork(v.version)}>fork</button>
+              {!v.current && <button class="cl-mini-btn" title="Promote to current" onClick={() => promote(v.version)}>promote</button>}
+            </div>
+          ))}
+          {versions.length >= 2 && (
+            <div class="cfg-compare">
+              <span class="hint">Compare</span>
+              <select class="prop-select" value={String(a ?? '')} onChange={(e) => setA(Number((e.target as HTMLSelectElement).value))}>
+                {versions.map(v => <option key={v.version} value={v.version}>v{v.version}</option>)}
+              </select>
+              <span>→</span>
+              <select class="prop-select" value={String(b ?? '')} onChange={(e) => setB(Number((e.target as HTMLSelectElement).value))}>
+                {versions.map(v => <option key={v.version} value={v.version}>v{v.version}</option>)}
+              </select>
+              <button class="panel-btn" disabled={a === null || b === null} onClick={() => onCompare(a!, b!)}>Diff</button>
+            </div>
+          )}
+        </div>
+      )}
+    </div>
+  );
+}
+
+// ── Diff views ────────────────────────────────────────────────────────────────
+
+function DiffModal({ title, onClose, children }: { title: string; onClose: () => void; children: any }) {
+  return (
+    <div class="cl-confirm-overlay" onMouseDown={(e) => { if (e.target === e.currentTarget) onClose(); }}>
+      <div class="cl-confirm cfg-diff-modal">
+        <div class="cfg-diff-head">
+          <span class="cl-confirm-title">Diff — {title}</span>
+          <button class="panel-btn" onClick={onClose}>Close</button>
+        </div>
+        {children}
+      </div>
+    </div>
+  );
+}
+
+function paramSummary(p?: Parameter): string {
+  if (!p) return '—';
+  const parts = [`${p.ds}:${p.signal}`, p.type];
+  if (p.default !== undefined) parts.push(`default=${p.default}`);
+  if (p.mandatory) parts.push('mandatory');
+  if (p.min !== undefined) parts.push(`min=${p.min}`);
+  if (p.max !== undefined) parts.push(`max=${p.max}`);
+  return parts.join(', ');
+}
+
+function SetDiffTable({ entries }: { entries: SetDiffEntry[] }) {
+  if (entries.length === 0) return <div class="hint">No parameters.</div>;
+  return (
+    <table class="cfg-diff-table">
+      <thead><tr><th>Parameter</th><th>Left</th><th>Right</th></tr></thead>
+      <tbody>
+        {entries.map(e => (
+          <tr key={e.key} class={`cfg-diff-${e.status}`}>
+            <td>{e.key} <span class="cfg-diff-status">{e.status}</span></td>
+            <td>{paramSummary(e.left)}</td>
+            <td>{paramSummary(e.right)}</td>
+          </tr>
+        ))}
+      </tbody>
+    </table>
+  );
+}
+
+function InstanceDiffTable({ entries }: { entries: InstanceDiffEntry[] }) {
+  if (entries.length === 0) return <div class="hint">No values.</div>;
+  return (
+    <table class="cfg-diff-table">
+      <thead><tr><th>Parameter</th><th>Left</th><th>Right</th></tr></thead>
+      <tbody>
+        {entries.map(e => (
+          <tr key={e.key} class={`cfg-diff-${e.status}`}>
+            <td>{e.key} <span class="cfg-diff-status">{e.status}</span></td>
+            <td>{e.left !== undefined ? String(e.left) : '—'}</td>
+            <td>{e.right !== undefined ? String(e.right) : '—'}</td>
+          </tr>
+        ))}
+      </tbody>
+    </table>
+  );
+}
+
+// ── small helpers ─────────────────────────────────────────────────────────────
+
+function msg(err: unknown): string { return err instanceof Error ? err.message : String(err); }
+function jsonPost(body: any): RequestInit { return { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) }; }
+function jsonPut(body: any): RequestInit { return { method: 'PUT', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) }; }
+function numOrUndef(v: string): number | undefined { if (v.trim() === '') return undefined; const n = Number(v); return isNaN(n) ? undefined : n; }
+function coerceVal(v: string, type: ParamType): any {
+  if (type === 'float64' || type === 'int64') { const n = Number(v); return isNaN(n) ? v : n; }
+  return v;
+}

web/src/PropertiesPane.tsx

@@ -302,6 +302,7 @@ export default function PropertiesPane({ selected, multiCount, iface, onChange,
                       <option value="fft">FFT</option>
                       <option value="waterfall">Waterfall</option>
                       <option value="logic">Logic analyser</option>
+                      <option value="waveform">Waveform (array)</option>
                     </select>
                   </Field>
                   {(w.options['plotType'] ?? 'timeseries') === 'timeseries' && (

web/src/SyntheticGraphEditor.tsx

@@ -3,9 +3,10 @@ import { useState, useEffect, useRef } from 'preact/hooks';
 import SignalPicker, { SignalOption } from './SignalPicker';
 import LuaEditor from './LuaEditor';
 import type { SignalDef, SynthGraph, SynthGraphNode } from './lib/types';
+import { inferNodeTypes, SynthType } from './lib/synthTypes';
 
 interface DataSource { name: string; }
-interface SignalInfo { name: string; }
+interface SignalInfo { name: string; type?: string; }
 
 interface Props {
   // Existing signal name (edit mode). Omitted/empty in create mode.
@@ -52,6 +53,18 @@ const OPS: OpDef[] = [
   ]},
   { type: 'expr',           label: 'Formula',        arity: { kind: 'named' }, params: [{ label: 'Expression', key: 'expr', type: 'text', default: 'a + b' }] },
   { type: 'lua',            label: 'Lua Script',     arity: { kind: 'named' }, params: [{ label: 'Script', key: 'script', type: 'lua', default: 'return a + b' }] },
+  // ── Array (waveform) ops ──
+  { type: 'index',          label: 'Index (a[i])',   arity: { kind: 'fixed', n: 1 }, params: [{ label: 'Index (i)', key: 'i', type: 'number', default: '0' }] },
+  { type: 'slice',          label: 'Slice',          arity: { kind: 'fixed', n: 1 }, params: [
+    { label: 'Start', key: 'start', type: 'number', default: '0' },
+    { label: 'End (0 = to end)', key: 'end', type: 'number', default: '0' },
+  ]},
+  { type: 'sum',            label: 'Sum (Σ array)',  arity: { kind: 'fixed', n: 1 }, params: [] },
+  { type: 'mean',           label: 'Mean (array)',   arity: { kind: 'fixed', n: 1 }, params: [] },
+  { type: 'min',            label: 'Min (array)',    arity: { kind: 'fixed', n: 1 }, params: [] },
+  { type: 'max',            label: 'Max (array)',    arity: { kind: 'fixed', n: 1 }, params: [] },
+  { type: 'length',         label: 'Length',         arity: { kind: 'fixed', n: 1 }, params: [] },
+  { type: 'fft',            label: 'FFT (magnitude)', arity: { kind: 'fixed', n: 1 }, params: [] },
 ];
 const OP_BY_TYPE = new Map(OPS.map(o => [o.type, o]));
 function opLabel(type: string): string { return OP_BY_TYPE.get(type)?.label ?? type; }
@@ -297,6 +310,9 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
   const [loading, setLoading] = useState(true);
   const [saving, setSaving] = useState(false);
   const [error, setError] = useState('');
+  // Quick-add HUD (S = signal, N = node); null when closed.
+  const [hud, setHud] = useState<null | 'signal' | 'node'>(null);
+  const [hudFilter, setHudFilter] = useState('');
 
   // Identity fields — editable only when creating a new signal.
   const [newName, setNewName] = useState('');
@@ -308,7 +324,7 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
   const sigName = create ? newName.trim() : (name ?? '');
 
   const [dataSources, setDataSources] = useState<string[]>([]);
-  const [dsSignals, setDsSignals] = useState<Record<string, string[]>>({});
+  const [dsSignals, setDsSignals] = useState<Record<string, SignalInfo[]>>({});
 
   const canvasRef = useRef<HTMLDivElement>(null);
   const dragNode = useRef<{ id: string; dx: number; dy: number; pushed: boolean } | null>(null);
@@ -338,7 +354,7 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
       const res = await fetch(`/api/v1/signals?ds=${encodeURIComponent(ds)}`);
       if (!res.ok) return;
       const sigs: SignalInfo[] = await res.json();
-      setDsSignals(prev => ({ ...prev, [ds]: sigs.map(s => s.name) }));
+      setDsSignals(prev => ({ ...prev, [ds]: sigs }));
     } catch {}
   }
 
@@ -346,11 +362,36 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
   // and a hook to lazily load all data sources' signals when a picker opens.
   function allSignalOptions(): SignalOption[] {
     const out: SignalOption[] = [];
-    for (const ds of dataSources) for (const name of (dsSignals[ds] ?? [])) out.push({ ds, name });
+    for (const ds of dataSources) for (const s of (dsSignals[ds] ?? [])) out.push({ ds, name: s.name });
     return out;
   }
   function openAllSignals() { dataSources.forEach(ds => loadSignals(ds)); }
 
+  // Resolve a source node's data type from the upstream signal's metadata.
+  // 'float64[]' is the only array type today; anything else is scalar, and an
+  // unresolved/unloaded source is 'unknown' (no error, runtime typing wins).
+  function sourceSynthType(n: SynthGraphNode): SynthType {
+    if (!n.ds || !n.signal) return 'unknown';
+    const sigs = dsSignals[n.ds];
+    if (!sigs) return 'unknown';
+    const info = sigs.find(s => s.name === n.signal);
+    if (!info || !info.type) return 'unknown';
+    return info.type === 'float64[]' ? 'array' : 'scalar';
+  }
+
+  // HUD filtering: case-insensitive substring over signal name/ds and op label/type.
+  function filteredSignalOptions(): SignalOption[] {
+    const q = hudFilter.trim().toLowerCase();
+    const all = allSignalOptions();
+    if (!q) return all;
+    return all.filter(o => o.name.toLowerCase().includes(q) || o.ds.toLowerCase().includes(q));
+  }
+  function filteredOps(): OpDef[] {
+    const q = hudFilter.trim().toLowerCase();
+    if (!q) return OPS;
+    return OPS.filter(o => o.label.toLowerCase().includes(q) || o.type.toLowerCase().includes(q));
+  }
+
   useEffect(() => {
     if (create) {
       const blank: SignalDef = { name: '', inputs: [], pipeline: [], meta: {} };
@@ -408,6 +449,20 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
     commit({ nodes: [...graph.nodes, node], wires: graph.wires });
     setSelected(node.id); setSelectedWire(null);
   }
+  // Add a source node pre-filled with a chosen ds:signal (used by the quick-add HUD).
+  function addSourceWith(ds: string, signal: string) {
+    const node: GNode = { id: genId(), kind: 'source', x: 2 * REM, y: (2 + graph.nodes.filter(n => n.kind === 'source').length * 5) * REM, ds, signal };
+    if (ds) loadSignals(ds);
+    commit({ nodes: [...graph.nodes, node], wires: graph.wires });
+    setSelected(node.id); setSelectedWire(null);
+  }
+  // Open the quick-add HUD; for signals, lazily load every source's signal list.
+  function openHud(kind: 'signal' | 'node') {
+    if (kind === 'signal') openAllSignals();
+    setHudFilter('');
+    setHud(kind);
+  }
+  function closeHud() { setHud(null); setHudFilter(''); }
   function addOp(op: OpDef, x?: number, y?: number) {
     const params: Record<string, any> = {};
     for (const p of op.params) params[p.key] = p.type === 'number' ? parseFloat(p.default) : p.default;
@@ -582,22 +637,34 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
       const mod = e.ctrlKey || e.metaKey;
       if (mod && e.key.toLowerCase() === 'z' && !e.shiftKey) { e.preventDefault(); undo(); return; }
       if (mod && (e.key.toLowerCase() === 'y' || (e.key.toLowerCase() === 'z' && e.shiftKey))) { e.preventDefault(); redo(); return; }
+      if (mod) return;
+      if (e.key === 'Escape') { if (hud) closeHud(); return; }
+      if (e.key.toLowerCase() === 's') { e.preventDefault(); openHud('signal'); return; }
+      if (e.key.toLowerCase() === 'n') { e.preventDefault(); openHud('node'); return; }
       if (e.key !== 'Delete' && e.key !== 'Backspace') return;
       if (selectedWire !== null) deleteWire(selectedWire);
       else if (selected) deleteNode(selected);
     }
     window.addEventListener('keydown', onKey);
     return () => window.removeEventListener('keydown', onKey);
-  }, [selected, selectedWire, graph]);
+  }, [selected, selectedWire, graph, hud]);
 
   const byId = new Map(graph.nodes.map(n => [n.id, n]));
   const sel = graph.nodes.find(n => n.id === selected) ?? null;
   const { errors: nodeErrors, first: validationError } = validate(graph);
 
+  // Static type propagation: infer each node's output type (scalar/array) to
+  // colour wires and surface type-incompatible wirings as node errors. Mirrors
+  // the backend dsp.OpOutputType rules (see lib/synthTypes.ts).
+  const { types: nodeTypes, errors: typeErrors } = inferNodeTypes(compile(graph), sourceSynthType);
+  for (const [id, msg] of typeErrors) if (!nodeErrors.has(id)) nodeErrors.set(id, msg);
+  const typeError = !validationError ? [...typeErrors.values()][0] : undefined;
+  const firstError = validationError ?? typeError;
+
   async function handleSave() {
     if (!def) return;
     if (create && !sigName) { setError('Enter a name for the new signal.'); return; }
-    if (validationError) { setError(validationError); return; }
+    if (firstError) { setError(firstError); return; }
     setSaving(true);
     setError('');
     try {
@@ -692,9 +759,10 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
                     const a = byId.get(w.from); const b = byId.get(w.to);
                     if (!a || !b) return null;
                     const p1 = outAnchor(a); const p2 = inAnchor(b, w.toPort);
+                    const tClass = nodeTypes.get(w.from) === 'array' ? ' synth-wire-array' : ' synth-wire-scalar';
                     return (
                       <path key={idx}
-                        class={`flow-wire${selectedWire === idx ? ' flow-wire-selected' : ''}`}
+                        class={`flow-wire${tClass}${selectedWire === idx ? ' flow-wire-selected' : ''}`}
                         d={wirePathStr(p1.x, p1.y, p2.x, p2.y)}
                         onClick={(e) => { e.stopPropagation(); setSelectedWire(idx); setSelected(null); }} />
                     );
@@ -712,6 +780,7 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
                   return (
                     <div key={node.id}
                       class={nodeClass(node)}
+                      title={nodeErrors.get(node.id) || undefined}
                       style={`left:${node.x}px; top:${node.y}px; width:${NODE_W}px; min-height:${nodeMinHeight(node, graph.wires)}px;`}
                       onMouseDown={(e) => startNodeDrag(e, node)}
                       onMouseUp={() => { if (pendingRef.current) finishWire(node, firstFreePort(node)); }}>
@@ -867,11 +936,57 @@ export default function SyntheticGraphEditor({ name, create, panelId, onClose, o
           </div>
         )}
 
+        {hud && (
+          <div class="synth-hud-backdrop" onMouseDown={closeHud}>
+            <div class="synth-hud" onMouseDown={(e) => e.stopPropagation()}>
+              <input
+                class="synth-hud-input"
+                autoFocus
+                placeholder={hud === 'signal' ? 'Add signal — filter by name…' : 'Add node — filter operations…'}
+                value={hudFilter}
+                onInput={(e) => setHudFilter((e.target as HTMLInputElement).value)}
+                onKeyDown={(e) => {
+                  if (e.key === 'Escape') { e.preventDefault(); closeHud(); return; }
+                  if (e.key === 'Enter') {
+                    e.preventDefault();
+                    if (hud === 'signal') {
+                      const opt = filteredSignalOptions()[0];
+                      if (opt) { addSourceWith(opt.ds, opt.name); closeHud(); }
+                    } else {
+                      const op = filteredOps()[0];
+                      if (op) { addOp(op); closeHud(); }
+                    }
+                  }
+                }} />
+              <div class="synth-hud-list">
+                {hud === 'signal'
+                  ? filteredSignalOptions().slice(0, 50).map(opt => (
+                      <button key={`${opt.ds}:${opt.name}`} class="synth-hud-item"
+                        onClick={() => { addSourceWith(opt.ds, opt.name); closeHud(); }}>
+                        <span class="synth-hud-item-name">{opt.name}</span>
+                        <span class="synth-hud-item-meta">{opt.ds}</span>
+                      </button>
+                    ))
+                  : filteredOps().map(op => (
+                      <button key={op.type} class="synth-hud-item"
+                        onClick={() => { addOp(op); closeHud(); }}>
+                        <span class="synth-hud-item-name">{op.label}</span>
+                        <span class="synth-hud-item-meta">{op.type}</span>
+                      </button>
+                    ))}
+                {hud === 'signal' && filteredSignalOptions().length === 0 && (
+                  <div class="hint synth-hud-empty">No matching signals.</div>
+                )}
+              </div>
+            </div>
+          </div>
+        )}
+
         <div class="wizard-footer">
           {error && <span class="wizard-error" style="flex:1;">{error}</span>}
-          {!error && validationError && <span class="hint" style="flex:1;">{validationError}</span>}
+          {!error && firstError && <span class="hint" style="flex:1;">{firstError}</span>}
           <button class="toolbar-btn" onClick={onClose}>Cancel</button>
-          <button class="toolbar-btn toolbar-btn-primary" onClick={handleSave} disabled={saving || loading || !!validationError}>
+          <button class="toolbar-btn toolbar-btn-primary" onClick={handleSave} disabled={saving || loading || !!firstError}>
             {saving ? 'Saving…' : 'Save Signal'}
           </button>
         </div>

web/src/ViewMode.tsx

@@ -11,6 +11,7 @@ import HelpModal from './HelpModal';
 import ZoomControl from './ZoomControl';
 import ControlLogicEditor from './ControlLogicEditor';
 import AuditViewer from './AuditViewer';
+import ConfigManager from './ConfigManager';
 
 interface Props {
   onEdit?: (iface?: Interface) => void;
@@ -34,6 +35,7 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
   const [showTimeNav, setShowTimeNav] = useState(false);
   const [showControlLogic, setShowControlLogic] = useState(false);
   const [showAudit, setShowAudit] = useState(false);
+  const [showConfig, setShowConfig] = useState(false);
   const [leftW, setLeftW] = useState(220);
   const [listCollapsed, setListCollapsed] = useState(false);
   const me = useAuth();
@@ -179,6 +181,15 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
               🛡 Audit
             </button>
           )}
+          {writable && (
+            <button
+              class="toolbar-btn"
+              onClick={() => setShowConfig(true)}
+              title="Open configuration manager"
+            >
+              🗂 Config
+            </button>
+          )}
           {writable && (
             <button
               class="btn-edit"
@@ -269,6 +280,9 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
       {showAudit && (
         <AuditViewer onClose={() => setShowAudit(false)} />
       )}
+      {showConfig && (
+        <ConfigManager onClose={() => setShowConfig(false)} />
+      )}
     </div>
   );
 }

web/src/lib/synthTypes.ts

@@ -0,0 +1,86 @@
+// Static type propagation for the synthetic node-graph editor. This mirrors the
+// Go runtime/compile rules in internal/dsp/types.go (OpOutputType) so the editor
+// can colour wires by data type and flag type-incompatible wirings before save.
+// Keep the two in sync — a parity test guards the pair.
+
+import type { SynthGraph, SynthGraphNode } from './types';
+
+export type SynthType = 'scalar' | 'array' | 'unknown';
+
+// reductionOps collapse an array (or scalar) to a single scalar.
+const REDUCTION_OPS = new Set(['index', 'length', 'sum', 'mean', 'min', 'max']);
+// arrayProducerOps require an array input and yield an array.
+const ARRAY_PRODUCER_OPS = new Set(['fft', 'slice']);
+// scalarOnlyOps reject array inputs and yield a scalar (stateful filters + lua).
+const SCALAR_ONLY_OPS = new Set(['moving_average', 'rms', 'lowpass', 'derivative', 'integrate', 'lua']);
+
+// opOutputType reports an op's output type given its input types, plus an error
+// message when the inputs are definitely incompatible with the op. 'unknown'
+// inputs (a source whose real type isn't known yet) never trigger an error —
+// runtime typing is authoritative.
+export function opOutputType(op: string, inputs: SynthType[]): { type: SynthType; error?: string } {
+  if (REDUCTION_OPS.has(op)) return { type: 'scalar' };
+
+  if (ARRAY_PRODUCER_OPS.has(op)) {
+    if (inputs.some(t => t === 'scalar')) return { type: 'unknown', error: `${op} requires an array input` };
+    return { type: 'array' };
+  }
+
+  if (SCALAR_ONLY_OPS.has(op)) {
+    if (inputs.some(t => t === 'array')) return { type: 'unknown', error: `${op} does not accept an array input` };
+    return { type: 'scalar' };
+  }
+
+  // Elementwise stateless ops (gain, offset, add, subtract, multiply, divide,
+  // clamp, threshold, expr): array if any input is an array, scalar if all
+  // inputs are definitely scalar, otherwise unknown.
+  if (inputs.some(t => t === 'array')) return { type: 'array' };
+  if (inputs.some(t => t === 'unknown')) return { type: 'unknown' };
+  return { type: 'scalar' };
+}
+
+// inferNodeTypes walks the DAG in dependency order and assigns each node an
+// output type. Source node types come from `sourceType` (resolved from upstream
+// signal metadata); unresolved sources default to 'unknown'. `errors` collects
+// per-node type-conflict messages for the editor's validation.
+export function inferNodeTypes(
+  g: SynthGraph,
+  sourceType: (n: SynthGraphNode) => SynthType,
+): { types: Map<string, SynthType>; errors: Map<string, string> } {
+  const types = new Map<string, SynthType>();
+  const errors = new Map<string, string>();
+  const byId = new Map(g.nodes.map(n => [n.id, n]));
+
+  // Kahn topological order over node inputs.
+  const indeg = new Map<string, number>();
+  const succ = new Map<string, string[]>();
+  for (const n of g.nodes) indeg.set(n.id, 0);
+  for (const n of g.nodes) {
+    for (const from of n.inputs ?? []) {
+      if (!byId.has(from)) continue;
+      indeg.set(n.id, (indeg.get(n.id) ?? 0) + 1);
+      succ.set(from, [...(succ.get(from) ?? []), n.id]);
+    }
+  }
+  const queue = g.nodes.filter(n => (indeg.get(n.id) ?? 0) === 0).map(n => n.id);
+  while (queue.length) {
+    const id = queue.shift()!;
+    const n = byId.get(id)!;
+    if (n.kind === 'source') {
+      types.set(id, sourceType(n));
+    } else if (n.kind === 'output') {
+      const from = (n.inputs ?? [])[0];
+      types.set(id, (from && types.get(from)) || 'unknown');
+    } else {
+      const inTypes = (n.inputs ?? []).map(f => types.get(f) ?? 'unknown');
+      const { type, error } = opOutputType(n.op ?? '', inTypes);
+      types.set(id, type);
+      if (error) errors.set(id, error);
+    }
+    for (const s of succ.get(id) ?? []) {
+      indeg.set(s, (indeg.get(s) ?? 0) - 1);
+      if ((indeg.get(s) ?? 0) === 0) queue.push(s);
+    }
+  }
+  return { types, errors };
+}

web/src/styles.css

@@ -375,6 +375,23 @@ body {
   /* width/height set inline from interface dimensions */
 }
 
+/* View mode: widgets shed their card chrome (border/background/shadow) so they
+   blend with the canvas background. Edit mode (EditCanvas) keeps the chrome so
+   widgets stay visible and selectable. Internal elements (gauge arc, bar track,
+   plot chart, inputs) keep their own styling. */
+.canvas-view-bare .textview,
+.canvas-view-bare .gauge,
+.canvas-view-bare .barh,
+.canvas-view-bare .barv,
+.canvas-view-bare .led-widget,
+.canvas-view-bare .multiled-widget,
+.canvas-view-bare .setvalue,
+.canvas-view-bare .plot-widget {
+  background: transparent;
+  border-color: transparent;
+  box-shadow: none;
+}
+
 /* ── TextLabel widget ──────────────────────────────────────────────────────── */
 
 .textlabel {
@@ -1248,6 +1265,12 @@ body {
 .flow-wire-selected { stroke: #ef4444; stroke-width: 2.5; }
 .flow-wire-pending { stroke: #3b82f6; stroke-dasharray: 5 4; }
 
+/* Synthetic-editor data-type wire colouring (scoped to .synth-graph so the
+   Logic / ControlLogic editors that share .flow-wire are unaffected). Scalar
+   keeps the default slate; array (waveform) signals are purple. */
+.synth-graph .flow-wire.synth-wire-array { stroke: #a855f7; }
+.synth-graph .flow-wire.synth-wire-array:hover { stroke: #c084fc; }
+
 /* Node block */
 .flow-node {
   position: absolute;
@@ -2002,8 +2025,64 @@ body {
   display: flex;
   flex-direction: column;
   box-shadow: 0 8px 32px rgba(0,0,0,0.5);
+  position: relative;
 }
 
+/* Quick-add HUD (S = signal, N = node) */
+.synth-hud-backdrop {
+  position: absolute;
+  inset: 0;
+  background: rgba(10, 14, 22, 0.45);
+  display: flex;
+  align-items: flex-start;
+  justify-content: center;
+  padding-top: 12vh;
+  z-index: 20;
+}
+.synth-hud {
+  width: 26rem;
+  max-width: 80%;
+  background: #1a1f2e;
+  border: 1px solid #3a4660;
+  border-radius: 8px;
+  box-shadow: 0 12px 40px rgba(0,0,0,0.55);
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+}
+.synth-hud-input {
+  border: none;
+  border-bottom: 1px solid #2d3748;
+  background: #0f1117;
+  color: #e2e8f0;
+  font-size: 0.9rem;
+  padding: 0.6rem 0.75rem;
+  outline: none;
+}
+.synth-hud-list {
+  max-height: 18rem;
+  overflow-y: auto;
+  display: flex;
+  flex-direction: column;
+}
+.synth-hud-item {
+  display: flex;
+  align-items: baseline;
+  justify-content: space-between;
+  gap: 0.5rem;
+  padding: 0.4rem 0.75rem;
+  background: none;
+  border: none;
+  color: #e2e8f0;
+  font-size: 0.85rem;
+  text-align: left;
+  cursor: pointer;
+}
+.synth-hud-item:hover { background: #243049; }
+.synth-hud-item-name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.synth-hud-item-meta { color: #64748b; font-size: 0.72rem; flex-shrink: 0; }
+.synth-hud-empty { padding: 0.6rem 0.75rem; }
+
 .wizard-header {
   display: flex;
   align-items: center;
@@ -3779,3 +3858,285 @@ kbd {
   background: #2563eb;
 }
 .panel-btn-primary:hover { background: #3b82f6; }
+
+/* ── Configuration manager ─────────────────────────────────────────────── */
+.cfg-tabs {
+  display: flex;
+  gap: 0.25rem;
+  margin-left: 0.5rem;
+}
+.cfg-tab {
+  background: transparent;
+  border: 1px solid transparent;
+  color: #94a3b8;
+  font-size: 0.82rem;
+  padding: 0.25rem 0.75rem;
+  border-radius: 6px;
+  cursor: pointer;
+}
+.cfg-tab:hover { color: #e2e8f0; background: #232a3a; }
+.cfg-tab-active {
+  color: #e2e8f0;
+  background: #2d3748;
+  border-color: #3d4a63;
+}
+.cfg-badge {
+  display: inline-block;
+  min-width: 1.1rem;
+  text-align: center;
+  font-size: 0.7rem;
+  color: #94a3b8;
+  background: #232a3a;
+  border-radius: 8px;
+  padding: 0 0.35rem;
+  margin-left: 0.4rem;
+}
+
+.cfg-editor {
+  display: flex;
+  flex-direction: column;
+  gap: 0.6rem;
+  padding: 0.75rem 1rem;
+  overflow-y: auto;
+  height: 100%;
+}
+.cfg-edit-bar {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+}
+.cfg-edit-bar .panel-btn { flex: 0 0 auto; }
+
+.cfg-section-head {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  margin-top: 0.5rem;
+  padding-bottom: 0.25rem;
+  border-bottom: 1px solid #2d3748;
+  font-size: 0.82rem;
+  font-weight: 600;
+  color: #cbd5e1;
+}
+.cfg-section-head .panel-btn { flex: 0 0 auto; }
+
+.cfg-params {
+  display: flex;
+  flex-direction: column;
+  gap: 0.5rem;
+}
+.cfg-param {
+  background: #151a26;
+  border: 1px solid #232a3a;
+  border-radius: 6px;
+  padding: 0.5rem;
+  position: relative;
+}
+.cfg-param-row {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.5rem;
+  align-items: flex-end;
+}
+.cfg-field {
+  display: flex;
+  flex-direction: column;
+  gap: 0.15rem;
+  min-width: 0;
+}
+.cfg-field > label {
+  font-size: 0.68rem;
+  text-transform: uppercase;
+  letter-spacing: 0.03em;
+  color: #64748b;
+}
+.cfg-field-key { width: 8rem; }
+.cfg-field-label { flex: 1; min-width: 8rem; }
+.cfg-field-type { width: 7rem; }
+.cfg-field-target { flex: 2; min-width: 12rem; }
+.cfg-field-default { width: 8rem; }
+.cfg-field-enum { flex: 1; min-width: 10rem; }
+.cfg-field-num { width: 6rem; }
+
+.cfg-mandatory {
+  display: flex;
+  flex-direction: row;
+  align-items: center;
+  gap: 0.3rem;
+  font-size: 0.75rem;
+  color: #94a3b8;
+  white-space: nowrap;
+  padding-bottom: 0.25rem;
+}
+.cfg-param-del {
+  background: transparent;
+  border: none;
+  color: #64748b;
+  cursor: pointer;
+  font-size: 1rem;
+  padding: 0 0.25rem;
+}
+.cfg-param-del:hover { color: #f87171; }
+
+.cfg-unit {
+  font-size: 0.72rem;
+  color: #64748b;
+  margin-left: 0.25rem;
+}
+
+/* ── Instance values ───────────────────────────────────────────────────── */
+.cfg-values {
+  display: flex;
+  flex-direction: column;
+  gap: 0.35rem;
+}
+.cfg-value-row {
+  display: flex;
+  align-items: center;
+  gap: 0.6rem;
+  padding: 0.3rem 0.4rem;
+  border-radius: 5px;
+}
+.cfg-value-row:hover { background: #151a26; }
+.cfg-value-label {
+  width: 14rem;
+  flex: 0 0 auto;
+  font-size: 0.82rem;
+  color: #cbd5e1;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.cfg-req { color: #f87171; margin-left: 0.15rem; }
+.cfg-value-input { width: 10rem; flex: 0 0 auto; }
+.cfg-value-target {
+  font-size: 0.72rem;
+  color: #64748b;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+/* ── Apply result ──────────────────────────────────────────────────────── */
+.cfg-apply-result {
+  border: 1px solid #232a3a;
+  border-radius: 6px;
+  margin-top: 0.5rem;
+  overflow: hidden;
+}
+.cfg-apply-head {
+  display: flex;
+  gap: 1rem;
+  padding: 0.4rem 0.6rem;
+  background: #151a26;
+  font-size: 0.8rem;
+  color: #cbd5e1;
+}
+.cfg-apply-table {
+  width: 100%;
+  border-collapse: collapse;
+  font-size: 0.78rem;
+}
+.cfg-apply-table th,
+.cfg-apply-table td {
+  text-align: left;
+  padding: 0.25rem 0.6rem;
+  border-top: 1px solid #1e2433;
+}
+.cfg-apply-table th { color: #64748b; font-weight: 500; }
+.cfg-ok { color: #4ade80; }
+.cfg-fail { color: #f87171; }
+
+/* ── Version panel ─────────────────────────────────────────────────────── */
+.cfg-versions {
+  border-top: 1px solid #2d3748;
+  margin-top: 0.5rem;
+  padding-top: 0.4rem;
+}
+.cfg-versions-toggle {
+  background: transparent;
+  border: none;
+  color: #94a3b8;
+  font-size: 0.8rem;
+  cursor: pointer;
+  padding: 0.2rem 0;
+}
+.cfg-versions-toggle:hover { color: #e2e8f0; }
+.cfg-versions-body {
+  display: flex;
+  flex-direction: column;
+  gap: 0.25rem;
+  margin-top: 0.4rem;
+}
+.cfg-version-row {
+  display: flex;
+  align-items: center;
+  gap: 0.6rem;
+  padding: 0.25rem 0.4rem;
+  border: 1px solid #232a3a;
+  border-radius: 5px;
+  font-size: 0.78rem;
+}
+.cfg-version-current {
+  border-color: #2563eb;
+  background: #15203a;
+}
+.cfg-version-num { font-weight: 600; color: #cbd5e1; min-width: 3rem; }
+.cfg-version-tag { color: #94a3b8; flex: 1; }
+.cfg-version-time { color: #64748b; font-size: 0.72rem; }
+.cfg-compare {
+  display: flex;
+  align-items: center;
+  gap: 0.4rem;
+  margin-top: 0.4rem;
+  font-size: 0.78rem;
+  color: #94a3b8;
+}
+
+/* ── Diff modal ────────────────────────────────────────────────────────── */
+.cfg-diff-modal {
+  background: #1a1f2e;
+  border: 1px solid #2d3748;
+  border-radius: 10px;
+  width: min(760px, 92vw);
+  max-height: 85vh;
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.6);
+}
+.cfg-diff-head {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 0.6rem 1rem;
+  border-bottom: 1px solid #2d3748;
+  font-size: 0.85rem;
+  color: #e2e8f0;
+}
+.cfg-diff-table {
+  width: 100%;
+  border-collapse: collapse;
+  font-size: 0.78rem;
+  overflow-y: auto;
+}
+.cfg-diff-table th,
+.cfg-diff-table td {
+  text-align: left;
+  padding: 0.3rem 0.7rem;
+  border-top: 1px solid #1e2433;
+  vertical-align: top;
+}
+.cfg-diff-table th { color: #64748b; font-weight: 500; }
+.cfg-diff-status {
+  font-size: 0.7rem;
+  text-transform: uppercase;
+  letter-spacing: 0.03em;
+}
+.cfg-diff-added { background: rgba(34, 197, 94, 0.08); }
+.cfg-diff-added .cfg-diff-status { color: #4ade80; }
+.cfg-diff-removed { background: rgba(239, 68, 68, 0.08); }
+.cfg-diff-removed .cfg-diff-status { color: #f87171; }
+.cfg-diff-changed { background: rgba(234, 179, 8, 0.08); }
+.cfg-diff-changed .cfg-diff-status { color: #facc15; }
+.cfg-diff-unchanged .cfg-diff-status { color: #64748b; }

web/src/widgets/PlotWidget.tsx

@@ -84,6 +84,8 @@ export default function PlotWidget({ widget, onContextMenu, timeRange }: Props)
     const showLegend = legendPos !== 'none';
 
     const buffers: SeriesBuffer[] = signals.map(() => ({ timestamps: [], values: [] }));
+    // Latest waveform (array) value per signal — used only by plotType 'waveform'.
+    const waveforms: number[][] = signals.map(() => []);
     const unsubs: (() => void)[] = [];
     const fmt = widget.options['format'] ?? '';
 
@@ -269,6 +271,24 @@ export default function PlotWidget({ widget, onContextMenu, timeRange }: Props)
             }),
           };
         }
+        case 'waveform': {
+          // Latest waveform (array) sample per signal, drawn as an x-vs-index
+          // trace. Each update replaces the trace rather than appending.
+          return {
+            backgroundColor: ECHARTS_DARK.backgroundColor,
+            legend: legendOpt,
+            grid: { left: 60, right: 16, top: showLegend ? 28 : 12, bottom: 40 },
+            xAxis: { type: 'value', name: 'Index', nameLocation: 'middle', nameGap: 24, min: 0, axisLine, axisLabel, splitLine },
+            yAxis: { type: 'value', name: 'Value', axisLine, axisLabel, splitLine },
+            series: signals.map((s, i) => ({
+              name: s.name,
+              type: 'line',
+              data: (waveforms[i] ?? []).map((v, k) => [k, v]),
+              lineStyle: { color: s.color ?? COLORS[i % COLORS.length] },
+              showSymbol: false,
+            })),
+          };
+        }
         case 'logic': {
           // Logic-analyser style: each signal is a 0/1 step trace stacked on its
           // own lane, with a relative-time x-axis (seconds before now).
@@ -423,7 +443,16 @@ export default function PlotWidget({ widget, onContextMenu, timeRange }: Props)
         if (sv.value === null || sv.value === undefined || sv.ts === null) return;
         const ts = new Date(sv.ts).getTime() / 1000;
 
-        if (plotType === 'timeseries') {
+        if (plotType === 'waveform') {
+          // Array-valued sample: keep only the latest waveform and redraw.
+          if (Array.isArray(sv.value)) {
+            waveforms[i] = sv.value.map((x: any) => typeof x === 'number' ? x : parseFloat(String(x)));
+          } else {
+            const v = typeof sv.value === 'number' ? sv.value : parseFloat(String(sv.value));
+            waveforms[i] = isNaN(v) ? [] : [v];
+          }
+          if (echart) echart.setOption(echartsOption(), { notMerge: true });
+        } else if (plotType === 'timeseries') {
           const v = typeof sv.value === 'number' ? sv.value : parseFloat(String(sv.value));
           if (isNaN(v)) return;
           pushSample(buffers[i], ts, v);