feat: 全站 PageShell 设计系统与专业 UI 统一

- 新增 PageShell/PageTabs/ContentPanel/PageLoading/PageEmpty 页面骨架
- index.css 设计令牌文档化，布局令牌与纯色主按钮（去除渐变粉彩）
- 全站路由页接入 PageShell，云账单三 Tab 为标杆
- 主题体系：跟随系统 + 主流/开发者分组，新增 Dracula/Tokyo Night，One Dark 暖灰差异化
- 登录页/侧栏/顶栏去渐变光球，企业克制风
- 修复 AIAlertAnalyzer JSX 与构建依赖导入问题

frontend/src/components/server/ExcelServerImport.tsx

@@ -315,7 +315,7 @@ export function ExcelServerImport({ open, onClose }: ExcelServerImportProps) {
                 <div className="flex items-center justify-between">
                   <div className="flex items-center gap-3">
                     <div className="w-10 h-10 rounded-lg bg-emerald-500/20 flex items-center justify-center">
-                      <FileSpreadsheet className="h-5 w-5 text-emerald-400" />
+                      <FileSpreadsheet className="h-5 w-5 dg-text-green" />
                     </div>
                     <div>
                       <p className="font-medium text-[var(--dg-text-primary)]">主机导入模板</p>
@@ -417,7 +417,7 @@ export function ExcelServerImport({ open, onClose }: ExcelServerImportProps) {
               <Card className="bg-[var(--dg-bg-secondary)] border-[var(--dg-border)]">
                 <CardContent className="p-3 flex items-center justify-between">
                   <div className="flex items-center gap-3">
-                    <FileSpreadsheet className="h-8 w-8 text-emerald-400" />
+                    <FileSpreadsheet className="h-8 w-8 dg-text-green" />
                     <div>
                       <p className="text-sm text-[var(--dg-text-primary)]">{selectedFile.name}</p>
                       <p className="text-xs text-[var(--dg-text-muted)]">{(selectedFile.size / 1024).toFixed(2)} KB</p>
@@ -426,7 +426,7 @@ export function ExcelServerImport({ open, onClose }: ExcelServerImportProps) {
                   <Button
                     variant="ghost"
                     size="icon"
-                    className="text-[var(--dg-text-muted)] hover:text-red-400"
+                    className="text-[var(--dg-text-muted)] hover:dg-text-red"
                     onClick={() => setSelectedFile(null)}
                   >
                     <X className="h-4 w-4" />
@@ -450,18 +450,18 @@ export function ExcelServerImport({ open, onClose }: ExcelServerImportProps) {
             <div className="flex items-center justify-between">
               <p className="text-[var(--dg-text-secondary)] text-sm">数据预览</p>
               <div className="flex items-center gap-2">
-                <Badge className="bg-emerald-500/20 text-emerald-400 border-0">
+                <Badge className="bg-emerald-500/20 dg-text-green border-0">
                   <Check className="h-3 w-3 mr-1" />
                   {validCount} 有效
                 </Badge>
                 {warningCount > 0 && (
-                  <Badge className="bg-amber-500/20 text-amber-400 border-0">
+                  <Badge className="bg-amber-500/20 dg-text-yellow border-0">
                     <AlertCircle className="h-3 w-3 mr-1" />
                     {warningCount} 警告
                   </Badge>
                 )}
                 {errorCount > 0 && (
-                  <Badge className="bg-red-500/20 text-red-400 border-0">
+                  <Badge className="bg-red-500/20 dg-text-red border-0">
                     <X className="h-3 w-3 mr-1" />
                     {errorCount} 错误
                   </Badge>
@@ -488,19 +488,19 @@ export function ExcelServerImport({ open, onClose }: ExcelServerImportProps) {
                       <td className="px-3 py-2">
                         <div className="flex items-center gap-1">
                           {row.status === 'valid' && (
-                            <Badge className="bg-emerald-500/20 text-emerald-400 border-0 text-xs">
+                            <Badge className="bg-emerald-500/20 dg-text-green border-0 text-xs">
                               <Check className="h-3 w-3 mr-1" />
                               {row.message}
                             </Badge>
                           )}
                           {row.status === 'warning' && (
-                            <Badge className="bg-amber-500/20 text-amber-400 border-0 text-xs">
+                            <Badge className="bg-amber-500/20 dg-text-yellow border-0 text-xs">
                               <AlertCircle className="h-3 w-3 mr-1" />
                               {row.message}
                             </Badge>
                           )}
                           {row.status === 'error' && (
-                            <Badge className="bg-red-500/20 text-red-400 border-0 text-xs">
+                            <Badge className="bg-red-500/20 dg-text-red border-0 text-xs">
                               <X className="h-3 w-3 mr-1" />
                               {row.message}
                             </Badge>
@@ -515,7 +515,7 @@ export function ExcelServerImport({ open, onClose }: ExcelServerImportProps) {
 
             {errorCount > 0 && (
               <div className="p-3 rounded-lg bg-red-500/10 border border-red-500/30">
-                <div className="flex items-center gap-2 text-red-400">
+                <div className="flex items-center gap-2 dg-text-red">
                   <AlertCircle className="h-4 w-4" />
                   <span className="text-sm">存在 {errorCount} 条错误数据，请修正后重新上传</span>
                 </div>