fix(frontend): 按审计报告修复全部17项问题,数据层迁至 src/api/

P0(4): 假数据清除(avg_latency_ms:2400→null,无端点字段改null)、假进度条改诚实的不确定态、
  公共页不再反向依赖 admin(api/public.ts)、PredictProgress 重写
P1(6): 23处 any 归零(对齐后端 Pydantic 契约新增 PredictionMatchRef/HealthProbe 等)、
  a11y(aria-live 0→4,htmlFor 1→17,aria-describedby/invalid 补齐)、App.tsx 抽 SiteLayout、
  路由级 lazy+代码分割(首屏 315KB→238KB)、index.html 补 SEO/favicon/OG、死代码清理(AdminIcon 抽出)
P2(7): Login/index.css 裸色值令牌化、groupByDate useMemo、滚动监听统一、原生控件基元化、
  useLeagues 静默失败补告警、路由级 ErrorBoundary

另修复审计未列问题:
- Monitoring todos 过滤器 t!==false 放行 null 导致整页崩溃 → Boolean(t) 真值过滤
- Collection 渲染期 Date.now()(react-hooks/purity 捕获)→ 计时器 effect
- bg-press-wash/60 透明度修饰符静默失效 → RGB 三元组 + 构建期令牌守卫(下个提交接入)

工程化:数据层 dal/api/types(1047行)git mv 至 src/api/,admin 留 @deprecated 兼容壳,
  21 个引用方直指新路径;tsconfig 开启 noUnusedLocals/noUnusedParameters(清理9处存量)

frontend/src/admin/Login.tsx

@@ -5,7 +5,8 @@
  */
 
 import { useState } from 'react'
-import { ApiError, login } from './api'
+import { ApiError, login } from '../api/api'
+import { Button, Input } from '../components/ui'
 
 export default function Login({ onSuccess }: { onSuccess: () => void }) {
   const [password, setPassword] = useState('')
@@ -50,12 +51,12 @@ export default function Login({ onSuccess }: { onSuccess: () => void }) {
       <main className="flex flex-1 items-start justify-center px-5 py-10">
         <form
           onSubmit={handleSubmit}
-          className="w-full max-w-sm border border-ink-300 bg-white p-6 shadow-[4px_4px_0_0_rgba(0,0,0,0.06)]"
+          className="w-full max-w-sm border border-ink-300 bg-paper-50 p-6 shadow-print"
         >
           <label htmlFor="admin-password" className="block text-xs font-medium tracking-wide text-ink-700">
             管理密码
           </label>
-          <input
+          <Input
             id="admin-password"
             type="password"
             value={password}
@@ -63,22 +64,27 @@ export default function Login({ onSuccess }: { onSuccess: () => void }) {
             placeholder="输入服务器 .env 中的 ADMIN_PASSWORD"
             autoFocus
             autoComplete="current-password"
-            className="field mt-2 w-full"
+            /* 错误时把输入框标记为无效并关联错误文本,
+               屏幕阅读器才能知道「密码错了」以及错在哪 */
+            aria-invalid={error ? true : undefined}
+            aria-describedby={error ? 'admin-password-error' : undefined}
+            className="mt-2 w-full"
           />
 
           {error && (
-            <p className="mt-3 border-l-2 border-press bg-press-wash/40 px-3 py-2 text-2xs leading-relaxed text-press-dark">
+            <p
+              id="admin-password-error"
+              /* role=alert 让错误出现时立即被朗读(aria-live 的 assertive 语义) */
+              role="alert"
+              className="mt-3 border-l-2 border-press bg-press-wash/40 px-3 py-2 text-2xs leading-relaxed text-press-dark"
+            >
               {error}
             </p>
           )}
 
-          <button
-            type="submit"
-            disabled={!password || submitting}
-            className="btn btn-solid mt-5 w-full justify-center"
-          >
+          <Button variant="solid" className="mt-5 w-full justify-center" type="submit" disabled={!password || submitting}>
             {submitting ? '验证中…' : '登 录'}
-          </button>
+          </Button>
 
           <p className="mt-4 border-t border-ink-200 pt-3 text-center text-2xs leading-relaxed text-ink-400">
             密码初始来自服务器 .env,可登录后在「系统配置」页修改;连续输错 5 次将锁定 10 分钟。