feat(storage): implement unified persistence layer with database models and repositories

backend/packages/storage/store/persistence/shared/__init__.py

@@ -0,0 +1,3 @@
+from .close import close_in_order
+
+__all__ = ["close_in_order"]

backend/packages/storage/store/persistence/shared/close.py

@@ -0,0 +1,29 @@
+from __future__ import annotations
+
+from collections.abc import Awaitable, Callable
+
+
+AsyncCloser = Callable[[], Awaitable[None]]
+
+
+async def close_in_order(*closers: AsyncCloser) -> None:
+    """
+    Run async closers in order and raise the first error, if any.
+
+    Notes
+    -----
+    - Used to keep driver-specific close logic readable.
+    - We intentionally do not stop at first failure, so later resources
+      still get a chance to close.
+    """
+    first_error: Exception | None = None
+
+    for closer in closers:
+        try:
+            await closer()
+        except Exception as exc:
+            if first_error is None:
+                first_error = exc
+
+    if first_error is not None:
+        raise first_error