fix: owner-less document query passes bare False to SQLAlchemy filter() (#1281)

* fix: use SQL false() for owner-less document query (filter(False) raises in SQLAlchemy 2.x)

* test: owner-less document query doesn't pass a bare False to filter

src/tool_implementations.py

@@ -90,7 +90,11 @@ def get_active_document():
 
 def _owned_document_query(query, Document, owner: Optional[str]):
     if owner is None:
-        return query.filter(False)
+        # A bare Python `False` is not a valid SQL expression — SQLAlchemy 1.4
+        # deprecates it and 2.0 raises ArgumentError. Use the SQL `false()`
+        # literal to return zero rows for an unscoped (owner-less) query.
+        from sqlalchemy import false
+        return query.filter(false())
     return query.filter(Document.owner == owner)