feat: restore mentor page to final day/night spec

Rebuild the mentor workspace per the approved final design (day.png/night.png):
- mentorView gets a dedicated full-width immersive shell (independent 56px
  top bar with page title slot + theme mode text, hidden module-nav/market
  tape/overview/status bar) scoped to body[data-active-view=mentorView].
- Assistant messages become borderless body text with name/time above; only
  user messages use a blue bubble; keep loading/error/streaming caret states.
- 4 quick topics stay visible with history; composer restored to a framed
  ~94px card with bottom-left shortcut hint and bottom-right send button.
- Directory tools merged into one row (search + filter menu + sort); the
  filter menu still offers all/A/B/C; list selected state is an inset rounded
  fill; contact rows are borderless 75px items.
- Chat header always shows pin/note/profile/clear; pin reuses /api/mentors/
  preferences; theme toggle stays the single #themeToggle.
- Night tokens match the spec including the two distinct blues (#316FEF link,
  #5B8DEF quote/selected icon). Mobile (<768) stacks panels with no horizontal
  overflow; 1024+ follows the desktop spec.
- Update stale test baselines (300px sidebar, 94px composer, hint presence,
  night bubble color, centered disclaimer) and regenerate the architecture
  inventory.

Co-authored-by: multica-agent <github@multica.ai>

app/frontend/index.html

@@ -17,9 +17,9 @@
       document.documentElement.style.colorScheme = theme;
     })();
   </script>
-  <link rel="stylesheet" href="/shared/tokens.css?v=20260806-2">
+  <link rel="stylesheet" href="/shared/tokens.css?v=20260818-1">
   <link rel="stylesheet" href="/shared/base.css?v=20260806-1">
-  <link rel="stylesheet" href="/shared/shell.css?v=20260806-2">
+  <link rel="stylesheet" href="/shared/shell.css?v=20260818-1">
   <link rel="stylesheet" href="/shared/auth.css?v=20260806-1">
   <link rel="stylesheet" href="/shared/components/controls.css?v=20260806-1">
   <link rel="stylesheet" href="/shared/components/navigation.css?v=20260806-1">
@@ -37,7 +37,7 @@
   <link rel="stylesheet" href="/pages/popularity/foundation.css?v=20260806-1">
   <link rel="stylesheet" href="/pages/dragon-tiger/foundation.css?v=20260806-1">
   <link rel="stylesheet" href="/pages/screener/foundation.css?v=20260806-2">
-  <link rel="stylesheet" href="/pages/mentor/foundation.css?v=20260806-2">
+  <link rel="stylesheet" href="/pages/mentor/foundation.css?v=20260818-1">
   <link rel="stylesheet" href="/pages/heaven/foundation.css?v=20260806-2">
   <link rel="stylesheet" href="/pages/review/foundation.css?v=20260806-1">
 </head>
@@ -68,6 +68,10 @@
       <span id="mobilePageGroup">行情</span>
       <strong id="mobilePageTitle">情绪周期</strong>
     </div>
+    <div class="app-page-context" aria-live="polite">
+      <strong id="currentPageTitle">小白复盘</strong>
+      <span id="currentPageSubtitle"></span>
+    </div>
     <div class="market-tape" aria-label="市场概况">
       <span class="market-item up">上涨 <strong id="tapeUp">--</strong></span>
       <span class="market-item down">下跌 <strong id="tapeDown">--</strong></span>
@@ -82,7 +86,7 @@
         <button id="nextDate" class="icon-button" type="button" title="后一个交易日" aria-label="后一个交易日"><i data-lucide="chevron-right"></i></button>
       </div>
       <button id="globalSearchButton" class="icon-button global-search-button" type="button" title="全局搜索（Ctrl+K）" aria-label="全局搜索"><i data-lucide="search"></i></button>
-      <button id="themeToggle" class="icon-button theme-toggle" type="button" title="切换到夜间模式" aria-label="切换到夜间模式" aria-pressed="false"><i data-lucide="moon"></i></button>
+      <button id="themeToggle" class="icon-button theme-toggle" type="button" title="切换到夜间模式" aria-label="切换到夜间模式" aria-pressed="false"><i data-lucide="moon"></i><span id="themeModeText">日间模式</span></button>
       <button id="alertButton" class="icon-button alert-button" type="button" title="提醒中心" aria-label="提醒中心"><i data-lucide="bell"></i><span id="alertBadge" class="alert-badge" hidden>0</span></button>
       <button id="assistantButton" class="icon-button assistant-button" type="button" title="复盘助手" aria-label="复盘助手"><i data-lucide="message-circle-more"></i></button>
       <button id="headerMenuButton" class="icon-button header-menu-button" type="button" title="打开命令菜单" aria-label="打开命令菜单" aria-expanded="false" aria-controls="headerCommandGroup"><i data-lucide="ellipsis"></i></button>
@@ -589,6 +593,8 @@
         <div class="settings-section-heading"><h3>公共行情</h3><span id="systemDataStatus">待检查</span></div>
         <label class="form-field"><span>Tushare Token</span><input id="systemTokenInput" type="password" autocomplete="off" minlength="20" placeholder="留空保留现有 Token"></label>
         <label class="form-field"><span>iFinD Refresh Token</span><input id="systemIfindTokenInput" type="password" autocomplete="off" maxlength="2048" placeholder="留空保留现有 Token"></label>
+        <label class="switch-control"><input id="systemIfindEnabled" type="checkbox"><span>启用 iFinD 数据源</span></label>
+        <p class="form-hint">默认停用。停用时仅保留凭据，不会发出任何 iFinD 请求；续费后开启此开关并保存即可恢复。</p>
         <label class="switch-control"><input id="systemBackgroundRefresh" type="checkbox"><span>启用交易时段后台刷新</span></label>
         <p class="form-hint">所有用户读取同一份后台快照，页面不会随后台任务自动重绘。</p>
         <div class="dialog-actions admin-inline-actions"><button id="adminRefreshButton" class="button" type="button"><i data-lucide="refresh-cw"></i>立即后台刷新</button><button class="button primary" type="submit">保存行情配置</button></div>