Enforce user locks for AI updates

docs/ARCHITECTURE.md

@@ -46,6 +46,9 @@ manual structure, arrangement, musical-parameter and production choices.
 When a Song Project uses Discuss mode, the AI Director sends the current
 project and conversation context to the provider and returns follow-up
 questions without applying a project update.
+All structured AI updates pass through a scope-aware merger. It applies only
+the scopes declared by the response, ignores user-locked scopes and preserves
+manual control values.
 
 ## Prompt Compiler
 

docs/DATA_MODEL.md

@@ -27,6 +27,7 @@ SongProject
 - lyrics
 - productionDirections[]
 - productionMode: manual | auto
+- userLocks[]
 - sunoOutput
 - versions[]
 - createdAt
@@ -76,6 +77,11 @@ Discuss mode behavior
   decision is applied.
 - A discussion response does not itself modify the Song Project.
 
+User-lock behavior
+- userLocks records update scopes explicitly locked by the user.
+- AI updates for locked scopes are ignored; every other accepted AI update must
+  still preserve Manual/Auto choices.
+
 InstrumentPlacement
 - sectionId (optional)
 - startTime (optional)

docs/TASKS.md

@@ -62,7 +62,7 @@ requirement is missing and blocks implementation, record it in
 -   [x] Implement Auto mode for structure, arrangement, BPM/key/maqam
     and production decisions.
 -   [x] Implement optional Discuss mode.
--   [ ] Enforce user-lock/manual-value precedence over AI output.
+-   [x] Enforce user-lock/manual-value precedence over AI output.
 -   [ ] Add error, retry, cancellation and rate-limit handling.
 
 ## Phase 5 --- Arabic Lyrics Processing