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/linux/nfpm/scripts/postinstall.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+# Update desktop database for .desktop file changes
+# This makes the application appear in application menus and registers its capabilities.
+if command -v update-desktop-database >/dev/null 2>&1; then
+  echo "Updating desktop database..."
+  update-desktop-database -q /usr/share/applications
+else
+  echo "Warning: update-desktop-database command not found. Desktop file may not be immediately recognized." >&2
+fi
+
+# Update MIME database for custom URL schemes (x-scheme-handler)
+# This ensures the system knows how to handle your custom protocols.
+if command -v update-mime-database >/dev/null 2>&1; then
+  echo "Updating MIME database..."
+  update-mime-database -n /usr/share/mime
+else
+  echo "Warning: update-mime-database command not found. Custom URL schemes may not be immediately recognized." >&2
+fi
+
+exit 0

build/linux/nfpm/scripts/postremove.sh

@@ -0,0 +1 @@
+#!/bin/bash

build/linux/nfpm/scripts/preinstall.sh

@@ -0,0 +1 @@
+#!/bin/bash

build/linux/nfpm/scripts/preremove.sh

@@ -0,0 +1 @@
+#!/bin/bash