- Add POST `/api/v1/config/hysteria/webpanel/decoy/setup` endpoint to configure the decoy site.
- Add POST `/api/v1/config/hysteria/webpanel/decoy/stop` endpoint to remove the decoy site configuration.
- Implement `BackgroundTasks` for both endpoints to prevent Caddy service restarts from interrupting the API response.
- Add `SetupDecoyRequest` Pydantic schema for the setup endpoint payload.