feat: local storage logic & endpoints

app/infrastructure/storage/provider.py

@@ -0,0 +1,16 @@
+"""File storage provider — singleton factory."""
+
+from app.core.config import get_settings
+from app.infrastructure.storage.local import LocalFileStorage
+
+_storage: LocalFileStorage | None = None
+
+
+def get_file_storage() -> LocalFileStorage:
+    global _storage
+    if _storage is None:
+        settings = get_settings()
+        if settings.storage_backend == "s3":
+            raise NotImplementedError("S3 storage not yet implemented.")
+        _storage = LocalFileStorage(settings.media_path)
+    return _storage