feat: add generation job cancel and retry queue

backend/app/api/stories.py

@@ -40,6 +40,7 @@ from app.services.generation_jobs import (
     get_user_generation_ops_summary,
     get_user_provider_analytics,
     list_story_generation_jobs,
+    request_generation_job_cancel,
 )
 from app.services.memory_service import build_enhanced_memory_context
 from app.services.provider_router import (
@@ -88,6 +89,32 @@ async def get_generation_job(
     return await get_generation_job_detail(db, job_id=job_id, user_id=user.id)
 
 
+@router.post(
+    "/generations/jobs/{job_id}/cancel",
+    response_model=GenerationJobSummaryResponse,
+)
+async def cancel_generation_job(
+    job_id: str,
+    user: User = Depends(require_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Request cancellation for one queued/running generation job."""
+    return await request_generation_job_cancel(db, job_id=job_id, user_id=user.id)
+
+
+@router.post(
+    "/generations/jobs/{job_id}/retry",
+    response_model=GenerationJobSummaryResponse,
+)
+async def retry_generation_job(
+    job_id: str,
+    user: User = Depends(require_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Queue one new generation job from a failed/canceled terminal job."""
+    return await story_service.retry_generation_job_service(job_id, user.id, db)
+
+
 @router.get(
     "/generations/ops-summary",
     response_model=GenerationOpsSummaryResponse,