重构：Wails v3 迁移 + 前端目录规范化 + Sidebar滚动优化

- web/ → frontend/ 目录重命名（Wails v3 标准结构）
- main.go: Middleware 修复 custom.js 404 + DevTools 延迟启动
- Sidebar: 收藏夹内部独立滚动 + 帮助区块固定底部
- useFavorites.ts: longPressTimer const→let 修复 TypeError
- App.vue: Arco Tabs padding-top 覆盖
- build: config.yml / Taskfile.yml 对齐官方模板，devtools build tag
- 新增 v3 bindings、vite.config.js、跨平台构建配置

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

build/darwin/Info.plist

@@ -0,0 +1,29 @@
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+    <dict>
+        <key>CFBundlePackageType</key>
+            <string>APPL</string>
+        <key>CFBundleName</key>
+            <string>U-Desk</string>
+        <key>CFBundleExecutable</key>
+            <string>u-desk.exe</string>
+        <key>CFBundleIdentifier</key>
+            <string>com.example.udesk</string>
+        <key>CFBundleVersion</key>
+            <string>0.1.0</string>
+        <key>CFBundleGetInfoString</key>
+            <string>This is a comment</string>
+        <key>CFBundleShortVersionString</key>
+            <string>0.1.0</string>
+        <key>CFBundleIconFile</key>
+            <string>icons</string>
+        <key>CFBundleIconName</key>
+            <string>appicon</string>
+        <key>LSMinimumSystemVersion</key>
+            <string>10.15.0</string>
+        <key>NSHighResolutionCapable</key>
+            <string>true</string>
+        <key>NSHumanReadableCopyright</key>
+            <string>© 2026, My Company</string>
+    </dict>
+</plist>