feat(frontend): 添加活动中心页面子包注册

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

cfc-frontend/pages.json

@@ -754,6 +754,19 @@
           "style": { "navigationBarTitleText": "加入家庭", "navigationStyle": "custom" }
         }
       ]
+    },
+    {
+      "root": "pages/activity",
+      "pages": [
+        {
+          "path": "index",
+          "style": { "navigationBarTitleText": "活动中心" }
+        },
+        {
+          "path": "activity-detail/activity-detail",
+          "style": { "navigationBarTitleText": "活动详情" }
+        }
+      ]
     }
   ],
   "globalStyle": {