fix(serve): handle null app_info when resource_agent references a deleted app

Add null check after self.get() in _resource_to_app_detail to prevent
AttributeError when a referenced app no longer exists.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: nishenghao.nsh

packages/derisk-serve/src/derisk_serve/building/app/service/service.py

@@ -734,6 +734,11 @@ def _resource_to_app_detail(
             logger.info(
                 f"[APP_DETAIL][PERF] _resource_to_app_detail 查询关联app[{app_code}]耗时: {(time.time() - _query_start) * 1000:.2f}ms"
             )
+            if not item_info:
+                logger.warning(
+                    f"[APP_DETAIL] _resource_to_app_detail 查询关联app[{app_code}]不存在，跳过"
+                )
+                continue
             details.append(
                 GptsAppDetail(
                     app_code=app_info.app_code,