feat: 新增 Tools 页面并重构 Skill 页面

- 添加 Tools.vue 工具管理页面
- 重构 Skill.vue 代码
- 更新路由和侧边栏导航

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/components/Sidebar.vue

@@ -54,7 +54,7 @@ const group2 = computed(() => [
 // 第3组: Skills, Tools, Script, Plan, Memory
 const group3 = computed(() => [
   { name: 'Skills', icon: 'fa-wand-magic-sparkles', badge: 21, path: '/mcp' },
-  { name: 'Tools', icon: 'fa-tools', badge: 13, path: '/model-apis' },
+  { name: 'Tools', icon: 'fa-tools', badge: 13, path: '/tools' },
   { name: 'Script', icon: 'fa-code', path: '/script' },
   { name: 'Plan', icon: 'fa-clock', path: '/plan' },
   { name: 'Memory', icon: 'fa-brain', path: '/memory' },