feat(storage): add local storage framework

backend/hermes/app/storage/schemas.py

@@ -0,0 +1,23 @@
+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass(frozen=True)
+class StoredFileMetadata:
+    storage_key: str
+    original_filename: str
+    stored_filename: str
+    relative_path: str
+    absolute_path: Path
+    mime_type: str
+    size: int
+    checksum_sha256: str
+
+
+@dataclass(frozen=True)
+class FileMetadata:
+    storage_key: str
+    relative_path: str
+    absolute_path: Path
+    size: int
+    checksum_sha256: str