chore(backlog): 记录 g102 完成

.ua/backlog.json

@@ -1179,7 +1179,7 @@
       "motivation": "modal 与 drawer 各自复制了一份 25 行的 Tab 焦点陷阱（focusables + keydown 环形回绕），改一处漏一处；image 的全屏预览层是 role=dialog aria-modal，却完全没有焦点陷阱也没把焦点移进去，键盘用户 Tab 一下就穿到背后的页面",
       "acceptance": "overlay.ts 新增 trapFocus(box, isOpen)：Tab / Shift+Tab 首尾环形，有无可用焦点与焦点在容器外的两种情况都拦回；modal / drawer 删掉本地实现改为调用（行为不变）；image 预览层补 tabindex=-1 + 打开即聚焦 + 全程锁焦点；npm run check 全绿",
       "notes": "自补：一致性与无障碍；陷阱实现单一来源，后续新增模态层直接复用",
-      "status": "open"
+      "status": "done"
     }
   ]
 }

.ua/iterations.log

@@ -146,3 +146,4 @@
 {"ts":"2026-10-26T13:17:13+08:00","id":"g99","result":"done","commit":"a5d4faf","summary":"spinner 新增 label 可访问名，缺省仍为加载中"}
 {"ts":"2026-10-26T13:17:42+08:00","id":"g100","result":"done","commit":"b190718","summary":"重新生成 CHANGELOG（273 提交），本次唤起 22 轮收尾"}
 {"ts":"2026-10-26T13:50:16+08:00","id":"g101","result":"done","commit":"265842e","summary":"新增 anchor 锚点导航：滚动高亮 + aria-current、offset 偏移定位、replaceState 写 hash，组件 57→58"}
+{"ts":"2026-10-26T13:51:46+08:00","id":"g102","result":"done","commit":"abfbb82","summary":"trapFocus 下沉到 overlay，modal/drawer 改调用，image 预览层补焦点锁与初始聚焦"}