feat(web): add Vue workspace with file tree, tabs, autosave and live sync

- Login and first-run setup screens
- File tree with inline create/rename, context menu, drag-and-drop
  move and trash with undo; all operations update the UI first and roll
  back on failure
- Tabs keep a CodeMirror state each; edits autosave after 500 ms with
  If-Match revisions, unsent edits persist in IndexedDB, and conflicts
  or remote deletions surface as banners with explicit choices
- WebSocket events sync external edits, moves and deletions into open
  tabs; reconnects trigger a full resync
- Pasted or dropped images show instantly and upload to note.assets/
- Responsive layout with a swipe-in sidebar drawer on phones
- Switch to TypeScript 6: vue-tsc does not support TypeScript 7 yet

web/src/main.ts

@@ -1,11 +1,6 @@
-// M0 原型入口：只挂载编辑器，M1 替换为 Vue 外壳
-import { createEditor } from './editor'
-import sample from './demo/sample.md?raw'
+import { createApp } from 'vue'
+import App from './app/App.vue'
 import './themes/base.css'
+import './app/app.css'
 
-// ?repeat=N 将示例重复 N 次，用于大文档性能测试
-const repeat = Number(new URLSearchParams(location.search).get('repeat') ?? 1)
-const doc = Array.from({ length: Math.max(1, repeat) }, () => sample).join('\n')
-
-const view = createEditor({ parent: document.getElementById('app')!, doc })
-;(window as unknown as { rawmarkView: typeof view }).rawmarkView = view
+createApp(App).mount('#app')