feat: add skill center navigation and travel request detail view

- Refactor audit to skill center for skill management
- Add TravelRequestDetailView for requests detail page
- Update PersonalWorkbench with enhanced features
- Add UI preview screenshots

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

src/composables/useNavigation.js

@@ -52,11 +52,11 @@ export const navItems = [
   },
   {
     id: 'audit',
-    label: '审计追踪',
-    navHint: '关键动作与日志',
-    icon: icons.audit,
-    title: '审计追踪',
-    desc: '查看关键审批动作、AI 建议和制度命中记录'
+    label: '技能中心',
+    navHint: 'Skill 设计与版本配置',
+    icon: icons.skill,
+    title: '技能中心',
+    desc: '统一管理技能的触发规则、提示词结构、输出约束与上线版本'
   }
 ]