优化: 设置域体验完善

- 校验失败红框定位字段,保存反馈改持久化成功后
- 数值越界钳制,双提示队列化不再重叠
- 搜索防抖跳分类,托盘气泡文案进多语言

src/i18n/en/aiChat.ts

@@ -292,5 +292,10 @@ export default {
     sendErrRateLimit: 'Rate limit reached, please retry later (error: {msg})',
     sendErrQuota: 'AI quota or balance insufficient, check your provider account (error: {msg})',
     sendErrNetwork: 'Network error or timeout, check your connection and retry (error: {msg})',
+
+    // ── UX-P3 chat polish additions ──
+    editEmptyBlocked: 'Edit content is empty, submission cancelled',
+    skillNoMatchQuery: 'No skill matches "{q}", send blocked',
+    backfillOverwriteConfirm: 'The input box has an unsent draft; backfilling will overwrite it. Continue?',
   },
 }