Code Review 第二轮修复:前端 HTTP 统一 + 数据采集可靠性

F1: 统一前端 HTTP 客户端
- 新增 frontend/src/lib/http.ts(共享客户端,统一超时/错误/401 处理)
- Matches.tsx 的列表/分页/进行中/预测请求改用 http 客户端
- 公开站与 Admin 行为一致

D2: events 采集按联赛分批提交
- _run_bzzoiro 改为 per-league 独立事务,避免超长事务
- 单联赛失败不影响其他联赛

F3: 仪表盘真实计数
- admin_stats 补充 matches/stats/standings 真实聚合
- Dashboard 展示比赛总数/已完赛/统计行/积分榜

F4: LLM 连通性测试不依赖 match_id=1
- 新增 POST /admin/llm/ping 端点(只发一次 chat,不依赖比赛)
- testLLMConnection 优先调用 ping,失败回退旧方式

F5: 导航改用 React Router Link
- App.tsx 中 <a href> 全部替换为 <Link to>

D5: 删除 away_possession 死代码
- bzzoiro.py 中移除计算与注释

D1: 管线基础设施表文档化
- RawEvent/IngestFailure/DataQualityCheck/DataLineage 添加「预留未启用」注释

Co-Authored-By: new-provider/LongCat-2.0 <<EMAIL>>

frontend/src/App.tsx

@@ -11,7 +11,7 @@
  * - 未登录访问管理 → AdminLayout 门禁 → 登录页(不静默失败)
  */
 
-import { BrowserRouter, Routes, Route, Navigate } from 'react-router-dom'
+import { BrowserRouter, Routes, Route, Navigate, Link } from 'react-router-dom'
 import { ErrorBoundary } from './components/ErrorBoundary'
 import Matches from './pages/Matches'
 import Standings from './pages/Standings'
@@ -40,15 +40,15 @@ function StandingsLayout({ children }: { children: React.ReactNode }) {
           <div className="flex items-center justify-between border-b border-ink-200 py-2 text-2xs text-ink-500">
             <span>{dateLine()}</span>
             <nav className="flex items-center gap-4" aria-label="页面导航">
-              <a href="/" className="text-ink-500 hover:text-press transition-colors">
+              <Link to="/" className="text-ink-500 hover:text-press transition-colors">
                 比赛 / 预测
-              </a>
-              <a href="/admin/eval" className="text-ink-500 hover:text-press transition-colors">
+              </Link>
+              <Link to="/admin/eval" className="text-ink-500 hover:text-press transition-colors">
                 评估
-              </a>
-              <a href="/admin" className="flex items-center gap-1 text-ink-500 hover:text-press transition-colors">
+              </Link>
+              <Link to="/admin" className="flex items-center gap-1 text-ink-500 hover:text-press transition-colors">
                 <span aria-hidden="true">⚙</span> 管理
-              </a>
+              </Link>
             </nav>
           </div>
         </div>
@@ -81,15 +81,15 @@ function HomePage() {
           <div className="flex items-center justify-between border-b border-ink-200 py-2 text-2xs text-ink-500">
             <span>{dateLine()}</span>
             <nav className="flex items-center gap-4" aria-label="页面导航">
-              <a href="/standings" className="text-ink-500 hover:text-press transition-colors">
+              <Link to="/standings" className="text-ink-500 hover:text-press transition-colors">
                 积分榜
-              </a>
-              <a href="/admin/eval" className="text-ink-500 hover:text-press transition-colors">
+              </Link>
+              <Link to="/admin/eval" className="text-ink-500 hover:text-press transition-colors">
                 评估
-              </a>
-              <a href="/admin" className="flex items-center gap-1 text-ink-500 hover:text-press transition-colors">
+              </Link>
+              <Link to="/admin" className="flex items-center gap-1 text-ink-500 hover:text-press transition-colors">
                 <span aria-hidden="true">⚙</span> 管理
-              </a>
+              </Link>
             </nav>
           </div>
         </div>