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/kubernetes/deployment-view/HistoryTab.tsx

@@ -39,7 +39,7 @@ export function HistoryTab({ revisions, rollbackLoading, onRollback }: { revisio
                 </TableCell>
                 <TableCell className="text-xs text-[var(--dg-text-muted)]">{formatK8sTime(rev.created_at || rev.time)}</TableCell>
                 <TableCell>
-                  <Button variant="ghost" size="sm" className="h-7 text-amber-400" disabled={isLatest || rollbackLoading !== null} onClick={() => onRollback(rev)}>
+                  <Button variant="ghost" size="sm" className="h-7 dg-text-yellow" disabled={isLatest || rollbackLoading !== null} onClick={() => onRollback(rev)}>
                     {rollbackLoading === revision ? <Loader2 className="h-3 w-3 animate-spin mr-1" /> : <RotateCcw className="h-3 w-3 mr-1" />}
                     回滚
                   </Button>

frontend/src/components/kubernetes/deployment-view/PodsTab.tsx

@@ -125,7 +125,7 @@ export function PodsTab({
                       {pod.ip || pod.pod_ip || '—'}
                     </span>
 
-                    <span className={`text-xs text-center font-mono ${(pod.restart_count || 0) > 0 ? 'text-amber-400' : 'text-[var(--dg-text-muted)]'}`}>
+                    <span className={`text-xs text-center font-mono ${(pod.restart_count || 0) > 0 ? 'dg-text-yellow' : 'text-[var(--dg-text-muted)]'}`}>
                       {pod.restart_count || 0}
                     </span>
 
@@ -134,10 +134,10 @@ export function PodsTab({
                     </span>
 
                     <div className="flex items-center justify-end gap-0.5 shrink-0 w-[88px]">
-                      <Button variant="ghost" size="sm" className="h-7 w-7 p-0 shrink-0 text-emerald-400" title="终端" onClick={() => onShowPodTerminal(pod)}>
+                      <Button variant="ghost" size="sm" className="h-7 w-7 p-0 shrink-0 dg-text-green" title="终端" onClick={() => onShowPodTerminal(pod)}>
                         <Terminal className="h-3.5 w-3.5" />
                       </Button>
-                      <Button variant="ghost" size="sm" className="h-7 w-7 p-0 shrink-0 text-amber-400" title="文件" onClick={() => onShowPodFileBrowser(pod)}>
+                      <Button variant="ghost" size="sm" className="h-7 w-7 p-0 shrink-0 dg-text-yellow" title="文件" onClick={() => onShowPodFileBrowser(pod)}>
                         <HardDrive className="h-3.5 w-3.5" />
                       </Button>
                       <DropdownMenu>
@@ -159,7 +159,7 @@ export function PodsTab({
                           <DropdownMenuItem onClick={() => onShowPodYaml(pod)} className="text-[var(--dg-text-primary)]">
                             <FileCode className="h-3.5 w-3.5 mr-2" /> YAML
                           </DropdownMenuItem>
-                          <DropdownMenuItem onClick={() => onDeletePod?.(pod)} className="text-red-400 focus:text-red-400">
+                          <DropdownMenuItem onClick={() => onDeletePod?.(pod)} className="dg-text-red focus:dg-text-red">
                             <Trash2 className="h-3.5 w-3.5 mr-2" /> 删除
                           </DropdownMenuItem>
                         </DropdownMenuContent>
@@ -179,7 +179,7 @@ export function PodsTab({
                               <div key={idx} className="rounded-md border border-[var(--dg-border)] bg-[var(--dg-bg-secondary)] px-3 py-2.5 text-xs">
                                 <div className="flex items-center justify-between gap-2">
                                   <span className="font-medium text-[var(--dg-text-primary)]">{String(c.name ?? '')}</span>
-                                  <span className={c.ready ? 'text-emerald-400' : 'text-[var(--dg-text-muted)]'}>
+                                  <span className={c.ready ? 'dg-text-green' : 'text-[var(--dg-text-muted)]'}>
                                     {c.ready ? 'Ready' : 'Pending'}
                                   </span>
                                 </div>