fix: Don't log asyncio.CancelledError as error - it's normal behavior

CancelledError is raised when async tasks are cancelled during shutdown
or connection close. This is normal asyncio behavior and should not be
logged as an error or counted in error metrics.

Fixes RUNTIME_ERROR caused by httpcore connection close triggering
async task cancellation in Gradio's internal queue operations.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -183,7 +183,7 @@ async def safe_async_wrapper(coro, operation_name: str = "async_operation"):
         return result
     except asyncio.CancelledError:
         logger.info(f"[ASYNC_CANCEL] {operation_name} was cancelled at {datetime.utcnow().isoformat()}Z")
-        write_error_log("async_cancelled", operation_name, "Operation was cancelled by asyncio")
+        # CancelledError is normal asyncio behavior - do NOT log as error
         raise  # Re-raise to allow proper cleanup
     except Exception as e:
         logger.error(f"[ASYNC_ERROR] {operation_name} failed: {e}")