codeQL fix

Author: Dhruvkumar-Microsoft

src/backend/v4/orchestration/human_approval_manager.py

@@ -132,6 +132,10 @@ async def _complete(self, messages: list[Message]) -> Message:
                     await asyncio.sleep(delay)
                     continue
                 raise
+        # If we get here, all retry attempts have been exhausted without a successful response.
+        raise RuntimeError(
+             f"Agent failed to complete after {max_retries} attempts due to repeated errors."
+         )
 
     async def plan(self, magentic_context: MagenticContext) -> Any:
         """