Minimal read-only FastAPI surface over the mirrored DB:
- GET /api/customers with pagination (page/page_size) and optional
channel / owner_account_id / department_id filters, ordered by
last_chat_time desc (nulls last) then friend_id.
- GET /api/health liveness probe.
- Pydantic v2 CustomerOut + generic Page[T] envelope.
- CORS configured permissively for the local frontend.
- Tests override get_session to an in-memory async SQLite session
(StaticPool) and drive the app via httpx ASGITransport.
Co-Authored-By: Claude <noreply@anthropic.com>