chore: make ty check blocking with targeted suppressions

Co-authored-by: Copilot App <[email protected]>

tests/test_storage_reconciliation.py

@@ -35,7 +35,14 @@ async def _document_ids(settings: Settings) -> set[str]:
 
 async def _source_counts_by_document(settings: Settings) -> dict[str, int]:
     async with session_scope(settings=settings) as session:
-        rows = await session.exec(select(Source.document_id, func.count(Source.id)).group_by(Source.document_id))
+        rows = await session.exec(
+            select(
+                Source.document_id,
+                func.count(Source.id),  # ty: ignore[invalid-argument-type] - SQLAlchemy descriptor false positive.
+            ).group_by(
+                Source.document_id  # ty: ignore[invalid-argument-type] - SQLAlchemy descriptor false positive.
+            )
+        )
         return {str(document_id): int(count) for document_id, count in rows}