fix(markdown): refresh previews after external changes

src/client/locales.ts

@@ -55,6 +55,8 @@ export const zh = {
   mermaidZoomReset: '重置',
   mermaidZoomHint: '滚轮缩放 · 拖拽平移 · Esc 关闭',
   refresh: '刷新',
+  fileChanged: '文件已更新',
+  refreshUnsavedConfirm: '文件已在磁盘更新，刷新将丢弃未保存编辑。继续吗？',
   save: '保存',
   saved: '已保存',
   unsaved: '未保存',
@@ -302,6 +304,8 @@ export const en: Record<keyof typeof zh, string> = {
   mermaidZoomReset: 'Reset',
   mermaidZoomHint: 'Scroll to zoom · drag to pan · Esc to close',
   refresh: 'Refresh',
+  fileChanged: 'File changed on disk',
+  refreshUnsavedConfirm: 'The file changed on disk. Refreshing will discard unsaved edits. Continue?',
   save: 'Save',
   saved: 'Saved',
   unsaved: 'Unsaved',