Improved perfs

internal/api/api.go

@@ -42,6 +42,9 @@ func (h *Handler) Register(mux *http.ServeMux, prefix string) {
 	mux.HandleFunc("PUT "+prefix+"/interfaces/{id}", h.updateInterface)
 	mux.HandleFunc("DELETE "+prefix+"/interfaces/{id}", h.deleteInterface)
 	mux.HandleFunc("POST "+prefix+"/interfaces/{id}/clone", h.cloneInterface)
+	// Signal group tree
+	mux.HandleFunc("GET "+prefix+"/groups", h.getGroups)
+	mux.HandleFunc("PUT "+prefix+"/groups", h.putGroups)
 	// Synthetic signal CRUD
 	mux.HandleFunc("GET "+prefix+"/synthetic", h.listSynthetic)
 	mux.HandleFunc("POST "+prefix+"/synthetic", h.createSynthetic)
@@ -184,6 +187,39 @@ func (h *Handler) channelFinder(w http.ResponseWriter, r *http.Request) {
 	jsonOK(w, names)
 }
 
+// ── /groups ───────────────────────────────────────────────────────────────────
+
+// getGroups returns the workspace group tree as a JSON array.
+func (h *Handler) getGroups(w http.ResponseWriter, r *http.Request) {
+	data, err := h.store.ReadGroups()
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	_, _ = w.Write(data)
+}
+
+// putGroups replaces the workspace group tree. The body must be a JSON array.
+func (h *Handler) putGroups(w http.ResponseWriter, r *http.Request) {
+	body, err := io.ReadAll(io.LimitReader(r.Body, 1<<20)) // 1 MB max
+	if err != nil {
+		http.Error(w, "read error", http.StatusBadRequest)
+		return
+	}
+	// Validate it is a JSON array (basic sanity check).
+	var raw []json.RawMessage
+	if err := json.Unmarshal(body, &raw); err != nil {
+		http.Error(w, "body must be a JSON array", http.StatusBadRequest)
+		return
+	}
+	if err := h.store.WriteGroups(body); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
 // ── /interfaces ───────────────────────────────────────────────────────────────
 
 func (h *Handler) listInterfaces(w http.ResponseWriter, r *http.Request) {