优化: 界面交互完善与设置体验

- 审批卡尊重滚动意图,等长切换回底,排队超时按钮修活
- 带图编辑提示不静默丢,删除目标回写,切换文案消歧
- 会话键盘可达+搜索态重命名,筛选计数口径对齐
- 子任务提示正名,看板加载态
- 主题跟随系统,表单脏态拦截,密钥显隐留空提示

src/i18n/en/settings.ts

@@ -54,6 +54,10 @@ export default {
     phProviderName: 'e.g. DeepSeek, GLM-4',
     phBaseUrl: 'https://api.deepseek.com',
     phApiKey: 'sk-...',
+    // UX-P2 walkthrough: API key show/hide toggle + "leave empty = keep" note
+    apiKeyShow: 'Show',
+    apiKeyHide: 'Hide',
+    apiKeyKeepHint: 'Leave empty while editing to keep the saved API key unchanged',
     phDefaultModel: 'deepseek-chat',
     // Direction A (lightweight): defaultModel is only a "suggested starting point";
     // guide users to hit "Test connection" to pull the vendor's real model list and overwrite,