chore(web): 删除 scan.html，清理 /scan/ nginx 路由和文档

scan.html 从未被实际触发——二维码 URL 格式为 /product/<uuid>，
由 Flutter Web PublicProductScreen 处理，scan.html 是孤立死页。

- 删除 web/scan.html
- 移除 nginx-jiu.conf 中 /scan/ location 块
- 更新文档路由表（/scan/<id> → /product/<uuid>）
- 标记 todo #4 完成

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

todo/todo.html

@@ -102,8 +102,8 @@ ul.todo-list { list-style: none; margin: 0; padding: 0; }
     <div class="header-meta">生成于 2026-06-08 · 真相源 todo/todo.json</div>
     <div class="stats">
       <div class="stat-pill"><strong>6</strong>全部</div>
-      <div class="stat-pill"><strong>5</strong>未完成</div>
-      <div class="stat-pill"><strong>1</strong>已完成</div>
+      <div class="stat-pill"><strong>4</strong>未完成</div>
+      <div class="stat-pill"><strong>2</strong>已完成</div>
     </div>
   </div>
 </header>
@@ -132,7 +132,7 @@ ul.todo-list { list-style: none; margin: 0; padding: 0; }
 
 <div class="wrap">
 
-  <div class="section-title">📋 未完成（5）</div>
+  <div class="section-title">📋 未完成（4）</div>
   <ul class="todo-list" id="pendingList">
     
     <li class="todo-card"
@@ -173,25 +173,6 @@ ul.todo-list { list-style: none; margin: 0; padding: 0; }
       </div>
     </li>
 
-    <li class="todo-card"
-        data-id="4"
-        data-level="low"
-        data-tags="前端,Web"
-        data-done="0">
-      <div class="card-header">
-        <span class="item-title">scan.html / features 走 passthrough 不享模板</span>
-        <span class="tag t-low">一般 / 优化</span>
-      </div>
-      <div class="item-desc">features/scan.html 直接复制，不经 njk 模板，页脚/备案/CSS 都得手动同步。建议长期改造为模板化。</div>
-      <div class="card-footer">
-        <div class="tag-row"><span class="tag t-tag" data-tag="前端">前端</span> <span class="tag t-tag" data-tag="Web">Web</span></div>
-        <div class="item-meta">
-      <span class="meta-date">🕐 2026-06-08</span>
-      
-    </div>
-      </div>
-    </li>
-
     <li class="todo-card"
         data-id="5"
         data-level="low"
@@ -232,10 +213,29 @@ ul.todo-list { list-style: none; margin: 0; padding: 0; }
   </ul>
 
   <div class="done-section">
-    <div class="section-title done-title">✅ 已完成（1）</div>
+    <div class="section-title done-title">✅ 已完成（2）</div>
     <button class="done-toggle" id="doneToggle">▾ 展开已完成列表</button>
     <ul class="todo-list hidden" id="doneList">
       
+    <li class="todo-card done"
+        data-id="4"
+        data-level="low"
+        data-tags="前端,Web"
+        data-done="1">
+      <div class="card-header">
+        <span class="item-title">scan.html / features 走 passthrough 不享模板</span>
+        <span class="tag t-low">一般 / 优化</span>
+      </div>
+      <div class="item-desc">features/scan.html 直接复制，不经 njk 模板，页脚/备案/CSS 都得手动同步。建议长期改造为模板化。</div>
+      <div class="card-footer">
+        <div class="tag-row"><span class="tag t-tag" data-tag="前端">前端</span> <span class="tag t-tag" data-tag="Web">Web</span></div>
+        <div class="item-meta">
+      <span class="meta-date">🕐 2026-06-08</span>
+      <span class="meta-date">✅ 完成 2026-06-08 · <span class="ver-badge">v1.0.23</span></span>
+    </div>
+      </div>
+    </li>
+
     <li class="todo-card done"
         data-id="1"
         data-level="mid"

todo/todo.json

@@ -1,7 +1,7 @@
 {
   "meta": {
     "title": "酒库管理系统 — 项目 TODO",
-    "updated_at": "2026-06-07T17:48:38.554Z"
+    "updated_at": "2026-06-07T18:07:13.211Z"
   },
   "seq": 7,
   "items": [
@@ -56,9 +56,9 @@
         "Web"
       ],
       "created_at": "2026-06-07T17:30:32.287Z",
-      "done": false,
-      "completed_at": null,
-      "version": null
+      "done": true,
+      "completed_at": "2026-06-07T18:07:13.211Z",
+      "version": "v1.0.23"
     },
     {
       "id": 5,