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/PodLogsViewer.tsx

@@ -337,9 +337,9 @@ export function PodLogsViewer({
           <div className="flex items-center gap-2 text-sm min-w-0">
             <div className={cn(
               'w-2 h-2 rounded-full shrink-0',
-              streaming ? (paused ? 'bg-amber-400' : 'bg-emerald-400 animate-pulse') : 'bg-slate-500'
+              streaming ? (paused ? 'bg-amber-400' : 'bg-emerald-400 animate-pulse') : 'bg-[var(--dg-bg-active)]'
             )} />
-            <ScrollText className="h-4 w-4 text-blue-400 shrink-0" />
+            <ScrollText className="h-4 w-4 dg-text-blue shrink-0" />
             <span className="text-[var(--dg-text-primary)] font-medium truncate">日志 — {podName}</span>
             {loading && <Loader2 className="h-3 w-3 animate-spin text-[var(--dg-text-muted)]" />}
             <span className="text-xs text-[var(--dg-text-muted)]">
@@ -472,7 +472,7 @@ export function PodLogsViewer({
             <>
               <Button
                 variant="outline" size="sm"
-                className={cn('h-8 text-xs', paused ? 'border-emerald-500 text-emerald-400' : 'border-amber-500 text-amber-400')}
+                className={cn('h-8 text-xs', paused ? 'border-emerald-500 dg-text-green' : 'border-amber-500 dg-text-yellow')}
                 onClick={() => setPaused(!paused)}
                 title={paused ? '继续' : '暂停'}
               >
@@ -481,7 +481,7 @@ export function PodLogsViewer({
               </Button>
               <Button
                 variant="outline" size="sm"
-                className="h-8 text-xs border-red-500 text-red-400"
+                className="h-8 text-xs border-red-500 dg-text-red"
                 onClick={stopStream}
                 title="停止"
               >
@@ -503,7 +503,7 @@ export function PodLogsViewer({
           }}
           className={cn(
             'overflow-auto bg-[#0f172a] font-mono text-xs leading-relaxed p-3',
-            'text-slate-300'
+            'text-[var(--dg-text-secondary)]'
           )}
           style={{ height: fullscreen ? 'calc(100vh - 98px)' : '520px' }}
         >
@@ -531,10 +531,10 @@ export function PodLogsViewer({
             <span className="flex items-center gap-1"><Filter className="h-3 w-3" />缓冲 {lineCount}/{RING_BUFFER_MAX}</span>
             {keyword && <span>匹配 {matchedCount}</span>}
             {container && <span className="flex items-center gap-1"><Box className="h-3 w-3" />{container}</span>}
-            {previous && <span className="text-amber-400 flex items-center gap-1"><History className="h-3 w-3" />previous</span>}
+            {previous && <span className="dg-text-yellow flex items-center gap-1"><History className="h-3 w-3" />previous</span>}
           </div>
           <button
-            className={cn('flex items-center gap-1', autoScroll ? 'text-emerald-400' : 'text-[var(--dg-text-muted)]')}
+            className={cn('flex items-center gap-1', autoScroll ? 'dg-text-green' : 'text-[var(--dg-text-muted)]')}
             onClick={() => {
               setAutoScroll(!autoScroll);
               if (!autoScroll && scrollRef.current) {