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/app/tree.ts

@@ -0,0 +1,46 @@
+import { computed, reactive, watch } from 'vue'
+import type { Entry } from './api'
+import { basename, dirname } from './paths'
+import { ws } from './workspace'
+
+export interface TreeNode {
+  name: string
+  path: string
+  dir: boolean
+  children: TreeNode[]
+}
+
+const collator = new Intl.Collator('zh-CN', { numeric: true, sensitivity: 'base' })
+
+function build(entries: Entry[]): TreeNode[] {
+  const root: TreeNode[] = []
+  const dirs = new Map<string, TreeNode>()
+  // 先按路径排序，保证父目录先于子项出现
+  for (const e of [...entries].sort((a, b) => a.path.length - b.path.length)) {
+    const node: TreeNode = { name: basename(e.path), path: e.path, dir: e.dir, children: [] }
+    if (e.dir) dirs.set(e.path, node)
+    ;(dirs.get(dirname(e.path))?.children ?? root).push(node)
+  }
+  const sort = (nodes: TreeNode[]) => {
+    nodes.sort((a, b) => (a.dir !== b.dir ? (a.dir ? -1 : 1) : collator.compare(a.name, b.name)))
+    nodes.forEach((n) => sort(n.children))
+  }
+  sort(root)
+  return root
+}
+
+export const tree = computed(() => build(ws.entries))
+
+const EXPANDED_KEY = 'rawmark.expanded'
+export const expanded = reactive(new Set<string>(JSON.parse(localStorage.getItem(EXPANDED_KEY) ?? '[]') as string[]))
+watch(expanded, () => localStorage.setItem(EXPANDED_KEY, JSON.stringify([...expanded])))
+
+// 打开或新建笔记时展开其所在的各级目录
+watch(
+  () => [ws.active, ws.renaming],
+  (paths) => {
+    for (const p of paths) {
+      for (let d = p ? dirname(p) : ''; d; d = dirname(d)) expanded.add(d)
+    }
+  },
+)