feat(M2): FR-S1/S4/S6 保存机制完善——setBody 防抖读 settings.autoSaveInterval(S1); beforeunload 冲刷+saveNow(S4); ReadDocResult 加 mtime+reloadDoc 检测外部改动(R6); store 暴露 __STORE__; save-mechanism E2E 3 项

apps/desktop/src/main/services/file-service.ts

@@ -140,8 +140,9 @@ export class FileService {
   async readDoc(path: string): Promise<ReadDocResult> {
     const abs = this.abs(path);
     const raw = await fs.readFile(abs, 'utf8');
+    const stat = await fs.stat(abs);
     const { meta, body } = splitFrontmatter(raw);
-    return { meta, body };
+    return { meta, body, mtime: stat.mtimeMs };
   }
 
   async writeDoc(payload: WriteDocPayload): Promise<void> {

apps/desktop/src/renderer/App.tsx

@@ -38,6 +38,12 @@ export function App() {
 
   useEffect(() => { loadVault(); loadTree(); restore(); appearance.load(); useKeymap.getState().load(); useSettings.getState().loadGpu(); }, []);
   useEffect(() => { if (activeId && tabs.length > 0) { const t = tabs.find(x => x.id === activeId); if (t) openDoc(t.path).catch(() => {}); } }, []);
+  // FR-S4：关窗前冲刷未保存内容
+  useEffect(() => {
+    const onBeforeUnload = () => { try { useStore.getState().saveNow(); } catch {} };
+    window.addEventListener('beforeunload', onBeforeUnload);
+    return () => window.removeEventListener('beforeunload', onBeforeUnload);
+  }, []);
   useGlobalHotkeys({ onNewDoc: () => {}, onSave: () => useStore.getState().saveNow(), onFocusSearch: () => { const el = document.querySelector('input[placeholder*="搜索"]') as HTMLInputElement; el?.focus(); }, onToggleOutline: () => layout.toggleOutline(), onCheat: () => setShowCheat(true), onSettings: () => setShowSettings(true), onFind: () => { window.dispatchEvent(new CustomEvent('dsh-toggle-find')); } });
 
   // 编辑器样式随设置生效（FR-编辑器设置真实生效）

apps/desktop/src/renderer/store.ts

@@ -15,6 +15,7 @@ interface EditorState {
   body: string;
   meta: DocMeta;
   saveState: SaveState;
+  docMtime: number; // FR-S6：已加载文档的 mtime，用于检测外部改动
   tagFilter: string[]; // FR-R7：选中标签列表，FileTree 据此 AND 过滤
   // actions
   loadVault: () => Promise<void>;
@@ -28,6 +29,7 @@ interface EditorState {
   addLink: (link: string) => void;
   removeLink: (link: string) => void;
   saveNow: () => Promise<void>;
+  reloadDoc: () => Promise<boolean>; // FR-S6：重新加载——检测 mtime 变化，有未保存改动时返回 false 需确认
   resetEditor: () => void;                          // FR-V6: 切库时重置编辑区
   syncCurrentPath: (oldPath: string, newPath: string) => void; // FR-T7: 重命名/移动后同步当前文档路径
 }
@@ -45,6 +47,7 @@ export const useStore = create<EditorState>((set, get) => ({
   meta: {},
   saveState: 'saved',
   tagFilter: [],
+  docMtime: 0,
 
   loadVault: async () => {
     const vault = await invoke(IPC.vaultList, undefined as never);
@@ -66,7 +69,7 @@ export const useStore = create<EditorState>((set, get) => ({
     // 切换前冲刷当前文档
     await get().saveNow();
     const doc: ReadDocResult = await invoke(IPC.docRead, { path });
-    set({ currentPath: path, body: doc.body, meta: doc.meta, title: doc.meta.title ?? path.split('/').pop()!.replace(/\.md$/, ''), saveState: 'saved' });
+    set({ currentPath: path, body: doc.body, meta: doc.meta, title: doc.meta.title ?? path.split('/').pop()!.replace(/\.md$/, ''), saveState: 'saved', docMtime: doc.mtime });
     // 同步到标签页（如已存在则激活，否则新建）
     useTabs.getState().openTab(path);
   },
@@ -98,9 +101,10 @@ export const useStore = create<EditorState>((set, get) => ({
   },
   setBody: (body: string) => {
     set({ body, saveState: 'saving' });
-    // 防抖自动保存（M1：固定 600ms，M9 接设置间隔）
+    // FR-S1：防抖自动保存——间隔读 settings.autoSaveInterval（秒→毫秒）
     if (saveTimer) clearTimeout(saveTimer);
-    saveTimer = setTimeout(() => { get().saveNow(); }, 600);
+    const interval = (() => { try { const s = JSON.parse(localStorage.getItem('dsh-settings') ?? '{}'); return (s.autoSaveInterval ?? 1) * 1000; } catch { return 1000; } })();
+    saveTimer = setTimeout(() => { get().saveNow(); }, interval);
   },
 
   saveNow: async () => {
@@ -116,7 +120,20 @@ export const useStore = create<EditorState>((set, get) => ({
     }
   },
 
-  resetEditor: () => { set({ currentPath: null, title: '', body: '', meta: {}, saveState: 'saved' }); },
+  // FR-S6：重新加载文档——检测 mtime 变化，有未保存改动时返回 false 需确认
+  reloadDoc: async () => {
+    const { currentPath, docMtime, saveState } = get();
+    if (!currentPath) return false;
+    try {
+      const doc: ReadDocResult = await invoke(IPC.docRead, { path: currentPath });
+      if (doc.mtime === docMtime) return true; // 未变
+      if (saveState !== 'saved') return false; // 有未保存改动，需确认
+      set({ body: doc.body, meta: doc.meta, docMtime: doc.mtime, saveState: 'saved' });
+      return true;
+    } catch { return false; }
+  },
+
+  resetEditor: () => { set({ currentPath: null, title: '', body: '', meta: {}, saveState: 'saved', docMtime: 0 }); },
 
   syncCurrentPath: (oldPath, newPath) => {
     const { currentPath } = get();
@@ -124,4 +141,7 @@ export const useStore = create<EditorState>((set, get) => ({
     if (currentPath === oldPath) { set({ currentPath: newPath }); return; }
     if (oldPath && currentPath.startsWith(oldPath + '/')) set({ currentPath: newPath + currentPath.slice(oldPath.length) });
   },
-}));
+}));
+
+// FR-S6：暴露 store 供 E2E 验证
+if (typeof window !== 'undefined') (window as any).__STORE__ = useStore;

apps/desktop/tests/e2e/save-mechanism.spec.ts

@@ -0,0 +1,108 @@
+import { test, expect } from '@playwright/test';
+import { _electron as electron } from 'playwright';
+import { promises as fs } from 'node:fs';
+import nodePath from 'node:path';
+import os from 'node:os';
+
+const MAIN_JS = nodePath.join(process.cwd(), 'dist-electron/main/index.js');
+
+async function launch(userData: string) {
+  const app = await electron.launch({ args: ['--user-data-dir=' + userData, MAIN_JS] });
+  const page = await app.firstWindow();
+  await page.waitForLoadState('domcontentloaded');
+  const invoke = (ch: string, args: any) => page.evaluate(({ ch, args }) => (globalThis as any).dsh.invoke(ch, args), { ch, args });
+  return { app, page, invoke };
+}
+
+async function newDoc(a: { page: any; invoke: any }, title: string) {
+  await a.page.getByRole('button', { name: /新建文档/ }).click();
+  await a.page.getByPlaceholder(/输入文档标题/).fill(title);
+  await a.page.getByPlaceholder(/输入文档标题/).press('Enter');
+  await expect(a.page.getByTestId('tabbar').getByText(title, { exact: true })).toBeVisible({ timeout: 10000 });
+}
+
+// FR-S1：自动保存——停止输入后内容写入文件
+test('FR-S1：自动保存防抖写入', async () => {
+  const tmp = await fs.mkdtemp(nodePath.join(os.tmpdir(), 'hn-s1-'));
+  const userData = nodePath.join(tmp, 'userdata');
+  const vault = nodePath.join(tmp, 'vault');
+  await fs.mkdir(userData, { recursive: true });
+  await fs.mkdir(vault, { recursive: true });
+
+  const a = await launch(userData);
+  await a.invoke('vault:switch', { root: vault });
+  await newDoc(a, '自动保存测试');
+
+  // 输入内容
+  await a.page.locator('.ProseMirror').click();
+  await a.page.keyboard.type('autosave content');
+
+  // 等待自动保存（默认 1 秒间隔 + 防抖）
+  await expect.poll(async () => {
+    try { const f = await fs.readFile(nodePath.join(vault, '自动保存测试.md'), 'utf8'); return f.includes('autosave content'); }
+    catch { return false; }
+  }, { timeout: 10000 }).toBe(true);
+
+  await a.app.close();
+});
+
+// FR-S4：关闭窗口前冲刷未保存内容
+test('FR-S4：关窗冲刷未保存内容', async () => {
+  const tmp = await fs.mkdtemp(nodePath.join(os.tmpdir(), 'hn-s4-'));
+  const userData = nodePath.join(tmp, 'userdata');
+  const vault = nodePath.join(tmp, 'vault');
+  await fs.mkdir(userData, { recursive: true });
+  await fs.mkdir(vault, { recursive: true });
+
+  const a = await launch(userData);
+  await a.invoke('vault:switch', { root: vault });
+  await newDoc(a, '关窗测试');
+
+  await a.page.locator('.ProseMirror').click();
+  await a.page.keyboard.type('before-close-flush');
+  // 等一下让内容进入 store
+  await a.page.waitForTimeout(200);
+  // 手动触发 saveNow（模拟 beforeunload 冲刷）
+  await a.page.evaluate(() => (window as any).__STORE__?.getState?.().saveNow?.());
+  await a.page.waitForTimeout(500);
+  await a.app.close();
+
+  // 文件应包含内容（关窗前冲刷）
+  const fileContent = await fs.readFile(nodePath.join(vault, '关窗测试.md'), 'utf8');
+  expect(fileContent).toContain('before-close-flush');
+});
+
+// FR-S6：reloadDoc 检测 mtime 变化
+test('FR-S6：reloadDoc 检测外部改动', async () => {
+  const tmp = await fs.mkdtemp(nodePath.join(os.tmpdir(), 'hn-s6-'));
+  const userData = nodePath.join(tmp, 'userdata');
+  const vault = nodePath.join(tmp, 'vault');
+  await fs.mkdir(userData, { recursive: true });
+  await fs.mkdir(vault, { recursive: true });
+
+  const a = await launch(userData);
+  await a.invoke('vault:switch', { root: vault });
+  await newDoc(a, '重载测试');
+
+  await a.page.locator('.ProseMirror').click();
+  await a.page.keyboard.type('original');
+  await a.page.waitForTimeout(2000); // 等待自动保存
+
+  // 外部修改文件
+  const filePath = nodePath.join(vault, '重载测试.md');
+  await fs.writeFile(filePath, '---\ntitle: 重载测试\n---\nexternal-change');
+
+  // reloadDoc 应检测到 mtime 变化并重载（无未保存改动时）
+  const result = await a.page.evaluate(async () => {
+    const store = (window as any).__STORE__;
+    if (!store) return { error: 'no store' };
+    return await store.getState().reloadDoc();
+  });
+  console.log('RELOAD_RESULT', JSON.stringify(result));
+  expect(result).toBe(true);
+  // 验证 store 的 body 已更新为外部修改的内容
+  const storeBody = await a.page.evaluate(() => (window as any).__STORE__?.getState?.().body ?? '');
+  expect(storeBody).toContain('external-change');
+
+  await a.app.close();
+});

packages/shared/src/types/doc.ts

@@ -9,6 +9,7 @@ export interface DocMeta {
 export interface ReadDocResult {
   meta: DocMeta;
   body: string;
+  mtime: number; // FR-S6：文件修改时间戳，用于检测外部改动
 }
 
 export interface WriteDocPayload {