优化: i18n硬编码清扫(8文件20+处中文字符串替为i18n)

- ToolCard: 已等待 → aiTool.waitTime

- ErrorBoundary: 堆栈详情 → error.stackDetails

- TopBar: 10处硬编码(tooltip+section标签+单位) → aiChat.* keys

- FileExplorer: 4处工程操作title → fileExplorer.*

- Tasks: 快捷菜单4处 → tasks.*

- EnrichmentPanel: 取消关联 → aiChat.enrichmentDismiss

- PlanProgress: 复用已有 aiChat.conflictsPending

- WorkflowDagDisplay: 删除中文fallback(已有i18n key)

- vue-tsc + vite build 通过

src/i18n/en/error.ts

@@ -3,5 +3,6 @@ export default {
     title: 'Render Error',
     desc: 'This section failed to render due to an internal error. Try reloading.',
     retry: 'Retry',
+    stackDetails: 'Stack Details',
   },
 }