curo1305
3ed6dd494f
feat(03-02): extend StorageBackend ABC and MinIOBackend with presigned PUT and stat_object
- Add generate_presigned_put_url and stat_object abstract methods to StorageBackend ABC
- Extend MinIOBackend with dual client (self._client internal + self._public_client public)
- MinIOBackend.__init__ accepts optional public_endpoint param (RESEARCH.md Finding 3)
- generate_presigned_put_url uses self._public_client for browser-resolvable URLs
- stat_object uses self._client.stat_object and returns .size (authoritative, T-03-05)
- get_storage_backend() passes public_endpoint=settings.minio_public_endpoint
- config.py adds minio_public_endpoint field (RESEARCH.md Finding 3)
- docker-compose.yml: MINIO_API_CORS_ALLOW_ORIGIN on minio service (T-03-09)
- docker-compose.yml: MINIO_PUBLIC_ENDPOINT on backend service
- docker-compose.yml: new celery-beat service (RESEARCH.md Finding 10)