Add control logic engine, panel logic dialogs, logic-edit restriction

Introduce server-side control-logic flow graphs (cron/alarm triggers,
Lua blocks) with CRUD endpoints, panel-logic lifecycle triggers and
user-interaction dialog nodes, and a synthetic node-graph editor.

Add an optional logic-editor allowlist (server.logic_editors) gating who
may add/edit panel logic and control logic, surfaced via /api/v1/me and
enforced in the API; hide logic affordances in the UI accordingly.

Update README, example config, and functional/technical specs to cover
all current features (plot panels, panel/control logic, local variables,
access control) and refresh the in-app manual and contextual help.

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

uopi.example.toml

@@ -18,11 +18,17 @@ default_user        = ""
 # user  = "guest"
 # level = "readonly"
 
-# Named sets of users, referenced by per-panel sharing rules (future phases).
+# Named sets of users, referenced by per-panel sharing rules.
 # [[groups]]
 # name    = "operators"
 # members = ["alice", "bob"]
 
+# Optional: restrict who may add or edit panel logic (the <logic> block of
+# interfaces) AND server-side control logic. Entries are usernames or group
+# names. Empty/unset = no restriction (any writer may edit logic). Also settable
+# via UOPI_SERVER_LOGIC_EDITORS (space-separated).
+# logic_editors = ["operators", "alice"]
+
 [datasource.epics]
 enabled            = true
 ca_addr_list       = ""   # overrides EPICS_CA_ADDR_LIST if set
@@ -31,5 +37,4 @@ channel_finder_url = ""   # e.g. http://channelfinder:8080/ChannelFinder
 auto_sync_filter   = ""   # e.g. area=StorageRing or tags=production
 
 [datasource.synthetic]
-enabled          = true
-definitions_file = "./synthetic.json"
+enabled = true