feat(vibe): plan musical arcs and callbacks

backend/src/services/vibe-session-coordinator.service.test.ts

@@ -54,6 +54,7 @@ function setup() {
   const director = {
     buildPlan: vi.fn().mockResolvedValue([{ trackId: TRACK_ID, generatorId: 'comfort', relevance: 0.8, explanation: [] }]),
     buildState: vi.fn().mockResolvedValue({ energy: 0.5, noveltyHunger: 0.3 }),
+    replan: vi.fn().mockResolvedValue([{ trackId: TRACK_ID, generatorId: 'comfort', relevance: 0.8, explanation: [] }]),
   } as any;
   return { db, director, coordinator: new VibeSessionCoordinator(db, director) };
 }
@@ -80,6 +81,31 @@ describe('VibeSessionCoordinator', () => {
       .toEqual(['session_started']);
   });
 
+  it('persists a director-selected arc role and explainable sequence score', async () => {
+    const { db, director, coordinator } = setup();
+    (director.buildPlan as any).mockResolvedValueOnce([{
+      trackId: TRACK_ID, generatorId: 'discovery', relevance: 0.7, explanation: [{ predicate: 'near' }],
+      plan: {
+        slotRole: 'surprise', score: 0.82,
+        scoreBreakdown: { relevance: 0.7, transition: 0.9, arcTarget: 0.85 },
+        explanation: { arcRole: 'surprise', surprise: { recoveryRole: 'favorite' } },
+      },
+    }]);
+
+    await coordinator.start('user-1', {});
+
+    expect(db.publishVibePlan).toHaveBeenCalledWith(expect.objectContaining({
+      items: [expect.objectContaining({
+        slot_role: 'surprise', score: 0.82,
+        score_breakdown: expect.objectContaining({ transition: 0.9 }),
+        explanation: expect.objectContaining({
+          paths: [{ predicate: 'near' }],
+          planner: expect.objectContaining({ arcRole: 'surprise' }),
+        }),
+      })],
+    }));
+  });
+
   it('returns the canonical replacement on an idempotent material-event retry without replanning', async () => {
     const { db, coordinator } = setup();
     (db.recordVibeEvent as any).mockResolvedValueOnce({
@@ -118,13 +144,42 @@ describe('VibeSessionCoordinator', () => {
     const { db, director, coordinator } = setup();
     const response = await coordinator.appendEvent('user-1', SESSION_ID, { type: 'completed', trackId: TRACK_ID });
 
-    expect(director.buildPlan).toHaveBeenCalledWith('user-1', SESSION_ID, TRACK_ID);
+    expect(director.replan).toHaveBeenCalledWith(
+      'user-1', SESSION_ID, expect.any(Array), [TRACK_ID], TRACK_ID,
+      { excludedTrackIds: new Set() },
+    );
     expect(db.publishVibePlan).toHaveBeenCalledWith(expect.objectContaining({
       sessionId: SESSION_ID, reason: 'feedback:completed', items: [expect.objectContaining({ committed: false })],
     }));
     expect(response).toMatchObject({ replanned: true, replanReason: 'feedback:completed', planVersion: 2 });
   });
 
+  it('passes the durable unserved callback tail into the retention-aware replan', async () => {
+    const { db, director, coordinator } = setup();
+    (db.getVibePlan as any).mockResolvedValue({
+      ...plan(),
+      items: [{
+        ...plan().items[0],
+        slot_role: 'favorite',
+        explanation: {
+          paths: [],
+          planner: { arcRole: 'favorite', callback: { id: 'theme:0', phase: 'return' } },
+        },
+      }],
+    });
+
+    await coordinator.appendEvent('user-1', SESSION_ID, { type: 'completed', trackId: 'other-track' });
+
+    expect(director.replan).toHaveBeenCalledWith(
+      'user-1', SESSION_ID,
+      [expect.objectContaining({
+        trackId: TRACK_ID,
+        plan: expect.objectContaining({ slotRole: 'favorite', explanation: expect.objectContaining({ arcRole: 'favorite' }) }),
+      })],
+      ['other-track'], 'other-track', { excludedTrackIds: new Set() },
+    );
+  });
+
   it('keeps the durable seed excluded when feedback supplies a different local replan anchor', async () => {
     const { db, director, coordinator } = setup();
     const seedTrackId = '44444444-4444-4444-8444-444444444444';
@@ -132,9 +187,11 @@ describe('VibeSessionCoordinator', () => {
 
     await coordinator.appendEvent('user-1', SESSION_ID, { type: 'completed', trackId: TRACK_ID });
 
-    expect(director.buildPlan).toHaveBeenCalledWith(
+    expect(director.replan).toHaveBeenCalledWith(
       'user-1',
       SESSION_ID,
+      expect.any(Array),
+      [TRACK_ID],
       TRACK_ID,
       { excludedTrackIds: new Set([seedTrackId]) },
     );