Expand generation harness observability

backend/app/api/stories.py

@@ -24,6 +24,7 @@ from app.schemas.story_schemas import (
     GenerationProviderStatsResponse,
     GenerationRequest,
     GenerationResponse,
+    GenerationTraceSummaryResponse,
     StoryAssetRetryRequest,
     StoryAudioStatusResponse,
     StorybookRequest,
@@ -37,6 +38,7 @@ from app.services import story_service
 from app.services.generation_jobs import (
     get_generation_job_detail,
     get_story_provider_stats,
+    get_story_trace_summary,
     get_user_generation_ops_summary,
     get_user_provider_analytics,
     list_story_generation_jobs,
@@ -181,6 +183,25 @@ async def get_generation_provider_stats(
     )
 
 
+@router.get(
+    "/generations/{story_id}/trace-summary",
+    response_model=GenerationTraceSummaryResponse,
+)
+async def get_generation_trace_summary(
+    story_id: int,
+    days: int | None = Query(default=None, ge=1, le=365),
+    user: User = Depends(require_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Get workflow trace summary aggregated from generation job events."""
+    return await get_story_trace_summary(
+        db,
+        story_id=story_id,
+        user_id=user.id,
+        days=days,
+    )
+
+
 @router.get("/generations/{story_id}", response_model=StoryDetailResponse)
 async def get_generation(
     story_id: int,