feat(content): 小程序「政策」tab→资讯中心(分类feed)

- 新增 pages/content(资讯中心)：类别分段tab(政策/资讯/技能/动态) + published列表；政策分类下提供「政策测评」入口(原测评页保留非tab)
- 新增 pages/content-detail(资讯详情：title/summary/body)
- utils/content.js：listContent(cat)/cachedContent/getContent(公开 /opc/content)
- app.config：tab 政策→资讯(pages/content)、注册 content/content-detail、policy 保留注册
- custom-tab-bar：政策→资讯

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

miniprogram/src/app.config.js

@@ -12,6 +12,8 @@ export default {
     'pages/park-apply/index',
     'pages/cert-apply/index',
     'pages/park-transfer/index',
+    'pages/content/index',
+    'pages/content-detail/index',
     'pages/scan-login/index'
   ],
   window: {
@@ -31,8 +33,7 @@ export default {
       { pagePath: 'pages/booking/index', text: '活动' },
       { pagePath: 'pages/test/index', text: '测评' },
       { pagePath: 'pages/index/index', text: '首页' },
-      { pagePath: 'pages/policy/index', text: '政策' },
-      // { pagePath: 'pages/plan/index', text: '流程' },
+      { pagePath: 'pages/content/index', text: '资讯' },
       { pagePath: 'pages/mine/index', text: '我的' }
     ]
   }