fix: Complete playbackMode removal from messages and tests

The gate mode removal PR left several references to playbackMode in:
- messages.ts: MUTATING_MESSAGE_TYPES and STATE_MUTATING_BROADCASTS
- sync-classification.ts: SYNCED_ACTIONS
- Various test files with outdated counts and fixtures

Also updates live-session.test.ts to use stepCount:256 (truly invalid)
since Phase 29F polyrhythm support expanded VALID_STEP_COUNTS to
include 128.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: adewale

app/src/shared/messages.ts

@@ -38,7 +38,6 @@ export const MUTATING_MESSAGE_TYPES = new Set([
   'set_track_volume',
   'set_track_transpose',
   'set_track_step_count',
-  'set_track_playback_mode',  // Phase 26: Playback mode sync (oneshot/loop/etc)
   'set_effects',       // Phase 25: Audio effects sync
   'set_scale',         // Phase 29E: Key Assistant scale sync
   'set_fm_params',     // Phase 24: FM synth parameters
@@ -91,7 +90,6 @@ export const STATE_MUTATING_BROADCASTS = new Set([
   'track_volume_set',
   'track_transpose_set',
   'track_step_count_set',
-  'track_playback_mode_set',  // Phase 26: Playback mode changed
   'effects_changed',
   'scale_changed',     // Phase 29E: Key Assistant scale sync
   'fm_params_changed',

app/src/shared/sync-classification.ts

@@ -32,7 +32,6 @@ export const SYNCED_ACTIONS = new Set([
   'SET_TRACK_VOLUME',      // Track parameter - shared
   'SET_TRACK_TRANSPOSE',   // Track parameter - shared
   'SET_TRACK_STEP_COUNT',  // Track setting - shared
-  'SET_TRACK_PLAYBACK_MODE', // Track setting - shared (Phase 26)
   'SET_EFFECTS',           // Global effects - shared (Phase 25)
   'SET_FM_PARAMS',         // Track parameter - shared (Phase 24)
   'COPY_SEQUENCE',         // Grid edit - shared (Phase 26)

app/src/worker/types.test.ts

@@ -299,8 +299,8 @@ describe('isStateMutatingBroadcast', () => {
       'track_volume_set',
       'track_transpose_set',
       'track_step_count_set',
-      'track_playback_mode_set',  // Phase 26: Playback mode changed
       'effects_changed',
+      'scale_changed',     // Phase 29E: Key Assistant scale sync
       'fm_params_changed',
       'sequence_copied',   // Phase 26: Steps copied between tracks
       'sequence_moved',    // Phase 26: Steps moved between tracks
@@ -354,7 +354,6 @@ describe('isStateMutatingBroadcast', () => {
       'set_track_volume', // -> track_volume_set
       'set_track_transpose', // -> track_transpose_set
       'set_track_step_count', // -> track_step_count_set
-      'set_track_playback_mode', // -> track_playback_mode_set (Phase 26)
       'set_effects',     // -> effects_changed
       'set_scale',       // -> scale_changed (Phase 29E)
       'set_fm_params',   // -> fm_params_changed
@@ -400,7 +399,6 @@ describe('TEST-08: Published Session WebSocket Blocking', () => {
       'set_track_volume',
       'set_track_transpose',
       'set_track_step_count',
-      'set_track_playback_mode', // Phase 26: Playback mode sync
       'set_effects',
       'set_scale',             // Phase 29E: Key Assistant scale sync
       'set_fm_params',
@@ -454,7 +452,6 @@ describe('TEST-08: Published Session WebSocket Blocking', () => {
       'set_session_name',   // Session metadata sync
       'set_swing',
       'set_tempo',
-      'set_track_playback_mode',  // Phase 26: Playback mode sync
       'set_track_sample',
       'set_track_step_count',
       'set_track_transpose',

app/test/integration/live-session.test.ts

@@ -581,7 +581,7 @@ it('Router: accepts all valid step count options (4, 8, 12, 16, 24, 32, 64)', as
   }
 });
 
-it('Router: rejects invalid step count (e.g., 13)', async () => {
+it('Router: rejects invalid step count (e.g., 256 - exceeds max)', async () => {
   const response = await SELF.fetch('http://localhost/api/sessions', {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
@@ -591,13 +591,12 @@ it('Router: rejects invalid step count (e.g., 13)', async () => {
           id: 'invalid-track',
           name: 'Invalid',
           sampleId: 'kick',
-          steps: Array(13).fill(true),
-          parameterLocks: Array(13).fill(null),
+          steps: Array(256).fill(true),
+          parameterLocks: Array(256).fill(null),
           volume: 1,
           muted: false,
-          playbackMode: 'oneshot',
           transpose: 0,
-          stepCount: 13, // Invalid: not in [4, 8, 12, 16, 24, 32, 64]
+          stepCount: 256, // Invalid: exceeds max of 128
         }],
         tempo: 120,
         swing: 0,

app/test/integration/message-types.test.ts

@@ -39,8 +39,8 @@ describe('REFACTOR-02: Single MUTATING_MESSAGE_TYPES', () => {
         'set_track_volume',
         'set_track_transpose',
         'set_track_step_count',
-        'set_track_playback_mode',  // Phase 26
         'set_effects',
+        'set_scale',         // Phase 29E: Key Assistant scale sync
         'set_fm_params',
         'copy_sequence',    // Phase 26
         'move_sequence',    // Phase 26
@@ -143,8 +143,8 @@ describe('REFACTOR-02: Single MUTATING_MESSAGE_TYPES', () => {
         'set_track_volume': 'track_volume_set',
         'set_track_transpose': 'track_transpose_set',
         'set_track_step_count': 'track_step_count_set',
-        'set_track_playback_mode': 'track_playback_mode_set',  // Phase 26
         'set_effects': 'effects_changed',
+        'set_scale': 'scale_changed',  // Phase 29E: Key Assistant scale sync
         'set_fm_params': 'fm_params_changed',
         'copy_sequence': 'sequence_copied',    // Phase 26
         'move_sequence': 'sequence_moved',     // Phase 26

app/test/unit/mutation-types.test.ts

@@ -43,7 +43,6 @@ const ALL_HANDLED_MESSAGE_TYPES = [
   'set_track_volume',
   'set_track_transpose',
   'set_track_step_count',
-  'set_track_playback_mode',  // Phase 26: Playback mode sync
   'set_effects',  // Phase 25: Audio effects sync
   'set_scale',  // Phase 29E: Key Assistant scale sync
   'set_fm_params',  // Phase 23: FM synthesis params sync
@@ -78,7 +77,6 @@ describe('Mutation Type Definitions', () => {
       'set_track_volume',
       'set_track_transpose',
       'set_track_step_count',
-      'set_track_playback_mode',  // Phase 26: Playback mode sync
       'set_effects',  // Phase 25: Audio effects sync
       'set_scale',  // Phase 29E: Key Assistant scale sync
       'set_fm_params',  // Phase 23: FM synthesis params sync
@@ -183,19 +181,19 @@ describe('Mutation Type Definitions', () => {
  * per "My Ears, My Control" philosophy - each user controls their own mix.
  */
 describe('Published Session Protection', () => {
-  it('has exactly 18 mutation types to block', () => {
-    // 16 original + set_session_name + set_scale
-    expect(MUTATING_MESSAGE_TYPES.size).toBe(18);
+  it('has exactly 17 mutation types to block', () => {
+    // 15 original + set_session_name + set_scale (removed set_track_playback_mode)
+    expect(MUTATING_MESSAGE_TYPES.size).toBe(17);
   });
 
   it('has exactly 8 read-only types to allow', () => {
     // 6 original + mute_track + solo_track
     expect(READONLY_MESSAGE_TYPES.size).toBe(8);
   });
 
-  it('covers all 26 message types handled by the DO', () => {
+  it('covers all 25 message types handled by the DO', () => {
     const totalClassified = MUTATING_MESSAGE_TYPES.size + READONLY_MESSAGE_TYPES.size;
     expect(totalClassified).toBe(ALL_HANDLED_MESSAGE_TYPES.length);
-    expect(totalClassified).toBe(26);
+    expect(totalClassified).toBe(25);
   });
 });

app/test/unit/sync-classification.test.ts

@@ -47,7 +47,6 @@ const ALL_GRID_ACTION_TYPES = [
   'SET_TRACK_VOLUME',
   'SET_TRACK_TRANSPOSE',
   'SET_TRACK_STEP_COUNT',
-  'SET_TRACK_PLAYBACK_MODE',
   'SET_EFFECTS',
   'SET_FM_PARAMS',
   'COPY_SEQUENCE',
@@ -115,8 +114,6 @@ function createMockAction(type: string): GridAction {
       return { type: 'SET_TRACK_TRANSPOSE', trackId: 'test-track-1', transpose: 3 };
     case 'SET_TRACK_STEP_COUNT':
       return { type: 'SET_TRACK_STEP_COUNT', trackId: 'test-track-1', stepCount: 32 };
-    case 'SET_TRACK_PLAYBACK_MODE':
-      return { type: 'SET_TRACK_PLAYBACK_MODE', trackId: 'test-track-1', playbackMode: 'loop' };
     case 'SET_EFFECTS':
       return { type: 'SET_EFFECTS', effects: mockEffects };
     case 'SET_FM_PARAMS':
@@ -189,9 +186,9 @@ describe('Sync Classification Verification', () => {
     });
 
     it('has the expected number of classified actions', () => {
-      // 17 synced + 6 local-only + 6 internal = 29 total
+      // 16 synced + 6 local-only + 6 internal = 28 total
       const totalClassified = SYNCED_ACTIONS.size + LOCAL_ONLY_ACTIONS.size + INTERNAL_ACTIONS.size;
-      expect(totalClassified).toBe(29);
+      expect(totalClassified).toBe(28);
     });
   });