Implement automatic song project decisions

docs/ARCHITECTURE.md

@@ -40,6 +40,9 @@ macOS App
 OpenAI receives the user's intent plus private application rules and
 structured project state. AI output should be requested as structured
 data wherever possible, not treated as an unstructured chat transcript.
+For automatic decisions, the AI Director requests only enabled automatic
+scopes and merges the response into the current project while preserving
+manual structure, arrangement, musical-parameter and production choices.
 
 ## Prompt Compiler
 

docs/DATA_MODEL.md

@@ -20,11 +20,13 @@ SongProject
 - key
 - scale
 - maqam
+- structureMode: manual | auto
 - sections[]
 - instruments[]
 - vocalists[]
 - lyrics
 - productionDirections[]
+- productionMode: manual | auto
 - sunoOutput
 - versions[]
 - createdAt
@@ -59,6 +61,15 @@ InstrumentTrack
 - autoArrangementEnabled
 - placements[]
 
+Auto-decision behavior
+- The AI may update song sections only when structureMode is auto.
+- The AI may update an instrument's role, playing style and placements only
+  when autoArrangementEnabled is true for that selected instrument.
+- The AI may fill BPM, key, scale and maqam only when their individual
+  ManualAutoValue mode is auto.
+- The AI may update production directions only when productionMode is auto.
+- Manual values remain authoritative when automatic decisions are applied.
+
 InstrumentPlacement
 - sectionId (optional)
 - startTime (optional)

docs/TASKS.md

@@ -59,7 +59,7 @@ requirement is missing and blocks implementation, record it in
 -   [x] Define structured AI response schema for SongProject updates.
 -   [x] Implement idea → complete project generation.
 -   [x] Implement existing lyrics → correction/improvement flow.
--   [ ] Implement Auto mode for structure, arrangement, BPM/key/maqam
+-   [x] Implement Auto mode for structure, arrangement, BPM/key/maqam
     and production decisions.
 -   [ ] Implement optional Discuss mode.
 -   [ ] Enforce user-lock/manual-value precedence over AI output.