feat: improve memory cleanup when plan approve

Author: dori

src/mcp_as_a_judge/db/providers/sqlite_provider.py

@@ -345,8 +345,11 @@ async def delete_previous_plan(self, session_id: str) -> None:
                     return
 
                 # Delete records using SQL IN clause with underlying SQLAlchemy session
-                delete_stmt = delete(ConversationRecord).where(
-                    ConversationRecord.id.in_(record_ids_to_delete)
+                # Use the table name from ConversationRecord to avoid type issues
+                table_name = ConversationRecord.__tablename__
+                table = SQLModel.metadata.tables[table_name]
+                delete_stmt = delete(table).where(
+                    table.c.id.in_(record_ids_to_delete)
                 )
                 # Use the underlying SQLAlchemy session for delete operations
                 session.execute(delete_stmt)