feat: auto-avatar integration with TheAudioDB

- Added avatar_url, avatar_source, avatar_fetched_at columns to Creator
  model with Alembic migration 014
- New backend/services/avatar.py — TheAudioDB lookup with token-based
  name similarity scoring and genre overlap bonus
- New Celery task fetch_creator_avatar for background avatar fetching
- Admin endpoints: POST /creators/{id}/fetch-avatar (single) and
  POST /creators/fetch-all-avatars (batch for missing avatars)
- Wired avatar_url into CreatorRead, CreatorInfo, and CreatorBrowseItem
  schemas so all API responses include avatar data

backend/routers/pipeline.py

@@ -1306,6 +1306,48 @@ async def reindex_all(
     }
 
 
+# ── Admin: Avatar fetching ───────────────────────────────────────────────────
+
+@router.post("/admin/pipeline/creators/{creator_id}/fetch-avatar")
+async def fetch_creator_avatar(
+    creator_id: str,
+    db: AsyncSession = Depends(get_session),
+):
+    """Trigger avatar lookup from TheAudioDB for a single creator."""
+    from pipeline.stages import fetch_creator_avatar as _task
+
+    creator = (await db.execute(
+        select(Creator).where(Creator.id == creator_id)
+    )).scalar_one_or_none()
+    if not creator:
+        raise HTTPException(status_code=404, detail="Creator not found")
+
+    _task.delay(creator_id)
+    return {"status": "dispatched", "creator": creator.name, "creator_id": creator_id}
+
+
+@router.post("/admin/pipeline/creators/fetch-all-avatars")
+async def fetch_all_avatars(
+    db: AsyncSession = Depends(get_session),
+):
+    """Trigger avatar lookup for all creators missing avatars."""
+    from pipeline.stages import fetch_creator_avatar as _task
+
+    result = await db.execute(
+        select(Creator.id, Creator.name).where(
+            (Creator.avatar_url.is_(None)) | (Creator.avatar_source == "generated")
+        )
+    )
+    creators = result.all()
+
+    dispatched = 0
+    for cid, name in creators:
+        _task.delay(str(cid))
+        dispatched += 1
+
+    return {"status": "dispatched", "count": dispatched}
+
+
 # ── Admin: Worker status ─────────────────────────────────────────────────────
 
 WORKER_STATUS_CACHE_KEY = "chrysopedia:worker_status"

backend/schemas.py

@@ -37,6 +37,7 @@ class CreatorRead(CreatorBase):
     model_config = ConfigDict(from_attributes=True)
 
     id: uuid.UUID
+    avatar_url: str | None = None
     view_count: int = 0
     created_at: datetime
     updated_at: datetime
@@ -288,6 +289,7 @@ class CreatorInfo(BaseModel):
     name: str
     slug: str
     genres: list[str] | None = None
+    avatar_url: str | None = None
 
 
 class SourceVideoSummary(BaseModel):