ui: 优化侧边栏菜单分组

- 提成奖金从「团队」移到「薪酬」
- 待签合同从「首页」移到「团队」
- 「合规」拆分：风险中心/证据链条/规章制度保留，用工体检/医疗期/年度价值独立为「工具」组

frontend/src/components/layout/SidebarNav.tsx

@@ -37,7 +37,6 @@ const navGroups: NavGroup[] = [
     items: [
       { path: '/', label: '工作台', icon: LayoutDashboard },
       { path: '/calendar', label: '工作日历', icon: CalendarDays },
-      { path: '/esign', label: '待签合同', icon: PenTool },
     ],
   },
   {
@@ -45,12 +44,12 @@ const navGroups: NavGroup[] = [
     items: [
       { path: '/roster', label: '花名册', icon: Users },
       { path: '/org-chart', label: '组织架构', icon: Building2 },
+      { path: '/esign', label: '待签合同', icon: PenTool },
       { path: '/termination', label: '离职管理', icon: UserX },
       { path: '/training-records', label: '培训记录', icon: GraduationCap },
       { path: '/performance-records', label: '绩效考核', icon: TrendingUp },
       { path: '/disciplinary-records', label: '违纪记录', icon: AlertTriangle },
       { path: '/special-status', label: '特殊员工', icon: Heart },
-      { path: '/commission-bonus', label: '提成奖金', icon: DollarSign },
     ],
   },
   {
@@ -65,6 +64,7 @@ const navGroups: NavGroup[] = [
     items: [
       { path: '/money', label: '薪税管理', icon: Calculator },
       { path: '/social', label: '社保公积金', icon: Shield },
+      { path: '/commission-bonus', label: '提成奖金', icon: DollarSign },
       { path: '/salary-dashboard', label: '薪酬分析', icon: BarChart3 },
     ],
   },
@@ -81,6 +81,11 @@ const navGroups: NavGroup[] = [
       { path: '/risk-center', label: '风险中心', icon: ShieldAlert },
       { path: '/evidence', label: '证据链条', icon: FileSearch },
       { path: '/policies', label: '规章制度', icon: FileText },
+    ],
+  },
+  {
+    title: '工具',
+    items: [
       { path: '/tools/health-check', label: '用工体检', icon: Stethoscope },
       { path: '/tools/medical-period', label: '医疗期', icon: HeartPulse },
       { path: '/tools/annual-value', label: '年度价值', icon: Award },