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>

frontend/bindings/github.com/wailsapp/wails/v3/internal/eventcreate.ts

@@ -0,0 +1,9 @@
+//@ts-check
+// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
+// This file is automatically generated. DO NOT EDIT
+
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore: Unused imports
+import { Create as $Create } from "@wailsio/runtime";
+
+Object.freeze($Create.Events);

frontend/bindings/github.com/wailsapp/wails/v3/internal/eventdata.d.ts

@@ -0,0 +1,2 @@
+// Cynhyrchwyd y ffeil hon yn awtomatig. PEIDIWCH Â MODIWL
+// This file is automatically generated. DO NOT EDIT