chore(backlog): 记录 g341 完成

.ua/backlog.json

@@ -3455,6 +3455,15 @@
       "acceptance": "verify 新增检查：skin 包 toast.ts 必须含 aria-live 容器与 alert 抢占播报，删掉任一处即红",
       "status": "done",
       "notes": ""
+    },
+    {
+      "id": "g341",
+      "domain": "tune",
+      "title": "表单错误文案补读屏关联：只标 aria-invalid 等于只说「无效」不说原因",
+      "motivation": "formItem 校验失败时目前只给控件涂 aria-invalid，错误文案是一个没有 id 的 div。读屏用户 Tab 到字段只会听到「无效编辑框」，听到「至少 6 个字符」这类具体原因必须先离开输入框去找下面那行小字——所见与非所见两条体验分叉。同时 hint 辅助说明也没有关联，正常态下同样念不到。",
+      "acceptance": "① error / hint 各自带派生 id（全页唯一，多表单不串号）；② paint 时把 aria-describedby 落到控件根与内部原生控件：有错指错误区、无错指 hint（若存在）、都没有则摘掉属性；③ ua verify 新增三条断言（错误区派生 id / aria-describedby 落笔 / 校验通过后清除）把行为钉住；④ npm run check 全绿，样式与令牌零改动。",
+      "status": "done",
+      "notes": ""
     }
   ]
 }

.ua/iterations.log

@@ -385,3 +385,4 @@
 {"ts":"2026-10-27T02:14:56+08:00","id":"g338","result":"done","commit":"28972a0","summary":"toast 容器补 aria-live=polite 兜底播报，error 级别 role=alert 抢占"}
 {"ts":"2026-10-27T02:17:29+08:00","id":"g339","result":"done","commit":"e5943aa","summary":"四方向 45° 菱形箭头继承气泡底色，全令牌零新增字面量"}
 {"ts":"2026-10-27T02:19:48+08:00","id":"g340","result":"done","commit":"21b98ad","summary":"verify 新增 toast live 检查（负向自检红/恢复绿），aria-live 与 alert 抢apost不再可回退"}
+{"ts":"2026-10-27T02:22:54+08:00","id":"g341","result":"done","commit":"5d02c81","summary":"formItem 错误区与 hint 各带唯一 id，paint 时把 aria-describedby 落到控件（报错优先、无错指向 hint、都没有则摘掉），verify 补三条断言钉住"}