feat(web): 升级前端依赖并重构邮件编辑器

- 将前端包管理切换为 `pnpm`，新增工作区与锁文件，并同步更新 CI 与 Docker 构建流程。
- 引入 `tiptap` 重构邮件正文编辑器，支持预览、富文本样式、链接/图片编辑与日程卡片插入。
- 发送与定时发送新增确认提示，补充空主题、空正文和附件提醒。
- 更新 `README.md` 与 `SHADCN_RULES.md` 中的安装与检查命令。

apps/web/package.json

@@ -3,12 +3,13 @@
   "version": "0.1.0",
   "private": true,
   "type": "module",
+  "packageManager": "pnpm@10.28.2",
   "scripts": {
     "dev": "vite --host 0.0.0.0",
     "build": "tsc -b && vite build",
     "preview": "vite preview --host 0.0.0.0",
     "check:shadcn": "node scripts/check-shadcn.mjs",
-    "check": "npm run check:shadcn && npm run build"
+    "check": "pnpm run check:shadcn && pnpm run build"
   },
   "dependencies": {
     "@radix-ui/react-avatar": "^1.1.12",
@@ -24,6 +25,19 @@
     "@radix-ui/react-toast": "^1.2.2",
     "@radix-ui/react-tooltip": "^1.2.9",
     "@tanstack/react-query": "5.59.16",
+    "@tiptap/core": "^3.27.0",
+    "@tiptap/extension-color": "^3.27.0",
+    "@tiptap/extension-font-family": "^3.27.0",
+    "@tiptap/extension-highlight": "^3.27.0",
+    "@tiptap/extension-image": "^3.27.0",
+    "@tiptap/extension-link": "^3.27.0",
+    "@tiptap/extension-placeholder": "^3.27.0",
+    "@tiptap/extension-text-align": "^3.27.0",
+    "@tiptap/extension-text-style": "^3.27.0",
+    "@tiptap/extension-underline": "^3.27.0",
+    "@tiptap/pm": "^3.27.0",
+    "@tiptap/react": "^3.27.0",
+    "@tiptap/starter-kit": "^3.27.0",
     "class-variance-authority": "^0.7.0",
     "clsx": "2.1.1",
     "dompurify": "3.4.10",