feat: 部署到服务器+移动端适配+帮助系统RAG集成+网页图标

- 部署脚本 deploy.sh：一键部署到 154.8.162.18，端口3400，Nginx conf.d
- 应用名改为「企业用工专家」（登录/注册/侧边栏/员工端等6处）
- 移动端适配修复：Attendance/Dashboard/Settings/Contracts 6处grid响应式
- 帮助系统：HelpModal 组件 + TopNav 帮助图标 + RAG语义搜索集成
  - 后端 rag.service.ts 新增23条帮助种子数据 + searchHelp()
  - 前端搜索调用 /ai/rag/help-search，RAG不可用时回退关键词匹配
- 网页图标 favicon.svg（indigo主色+建筑人形图案）
- index.html 标题改为「企业用工专家」

frontend/src/pages/Attendance.tsx

@@ -56,7 +56,7 @@ export default function Attendance() {
 
       {/* 统计卡片 */}
       {stats && (
-        <div className="grid grid-cols-4 gap-2">
+        <div className="grid grid-cols-2 sm:grid-cols-4 gap-2">
           {[
             { label: '总计', value: stats.total, color: 'text-gray-700' },
             { label: '待确认', value: stats.pending, color: 'text-amber-600' },

frontend/src/pages/Contracts.tsx

@@ -318,7 +318,7 @@ function AddEmployeeModal({ open, onClose, onSubmit, loading, error }: {
             </div>
 
             {form.contractType === 'FIXED' && (
-              <div className="grid grid-cols-3 gap-3">
+              <div className="grid grid-cols-1 sm:grid-cols-3 gap-3">
                 <div>
                   <Label>合同结束日期</Label>
                   <Input type="date" value={form.endDate} onChange={(e) => setForm({ ...form, endDate: e.target.value })} />

frontend/src/pages/Dashboard.tsx

@@ -727,7 +727,7 @@ export default function Dashboard() {
               {/* 企业成本 */}
               <div className="border-t pt-2 space-y-2">
                 <div className="text-xs font-medium text-gray-600 mb-1">企业用工成本</div>
-                <div className="grid grid-cols-3 gap-2">
+                <div className="grid grid-cols-1 sm:grid-cols-3 gap-2">
                   <div className="flex items-center justify-between p-2 rounded-md bg-blue-50">
                     <span className="text-xs text-gray-500 flex items-center gap-1"><Building2 className="w-3 h-3" />企业社保</span>
                     <span className="text-xs font-medium text-blue-700">{fmt(payroll.socialOrg)}</span>

frontend/src/pages/Settings.tsx

@@ -174,7 +174,7 @@ function RetirementSection({ enabled, onToggle }: { enabled: boolean; onToggle:
   const renderPolicyRules = () => (
     <div className="space-y-2">
       <div className="text-xs font-medium text-gray-600">改革规则（基准退休年龄 → 目标退休年龄）</div>
-      <div className="grid grid-cols-3 gap-2">
+      <div className="grid grid-cols-1 sm:grid-cols-3 gap-2">
         <div className="bg-white rounded-md p-2 text-center border border-gray-200">
           <div className="text-xs text-gray-500">男性职工</div>
           <div className="text-sm font-semibold text-gray-700">60岁 → 63岁</div>
@@ -562,7 +562,7 @@ function PlanSettings({ orgData }: { orgData: any }) {
       {usageData && (
         <Card>
           <h3 className="text-xs font-medium text-gray-700 mb-3">当前用量</h3>
-          <div className="grid grid-cols-3 gap-4 text-xs">
+          <div className="grid grid-cols-1 sm:grid-cols-3 gap-4 text-xs">
             <div>
               <div className="text-gray-500">员工数</div>
               <div className="font-medium text-base">{usageData.employeeCount}<span className="text-gray-500 text-xs">/{usageData.maxEmployees}</span></div>

frontend/src/pages/auth/ForgotPassword.tsx

@@ -60,7 +60,7 @@ export default function ForgotPassword() {
       <div className="w-full max-w-sm">
         <div className="flex items-center justify-center gap-2 mb-8">
           <Building2 className="w-8 h-8 text-primary" />
-          <span className="text-xl font-bold">用工合规助手</span>
+          <span className="text-xl font-bold">企业用工专家</span>
         </div>
 
         <div className="card">

frontend/src/pages/auth/Login.tsx

@@ -50,7 +50,7 @@ export default function Login() {
       <div className="w-full max-w-sm">
         <div className="flex items-center justify-center gap-2 mb-8">
           <Building2 className="w-8 h-8 text-primary" />
-          <span className="text-xl font-bold">用工合规助手</span>
+          <span className="text-xl font-bold">企业用工专家</span>
         </div>
 
         <div className="card">

frontend/src/pages/auth/Register.tsx

@@ -51,7 +51,7 @@ export default function Register() {
       <div className="w-full max-w-sm">
         <div className="flex items-center justify-center gap-2 mb-8">
           <Building2 className="w-8 h-8 text-primary" />
-          <span className="text-xl font-bold">用工合规助手</span>
+          <span className="text-xl font-bold">企业用工专家</span>
         </div>
 
         <div className="card">

frontend/src/pages/portal/PortalLogin.tsx

@@ -64,7 +64,7 @@ export default function PortalLogin() {
       <div className="w-full max-w-sm">
         <div className="flex items-center justify-center gap-2 mb-8">
           <Building2 className="w-8 h-8 text-primary" />
-          <span className="text-base font-bold">用工合规助手 — 员工端</span>
+          <span className="text-base font-bold">企业用工专家 — 员工端</span>
         </div>
 
         <div className="card">