refactor: overhaul UI for streamlined user experience

Redesign navigation, home overview, user portrait, and valuation pages
with improved functionality and responsive design.

Co-authored-by: null <4804959+fnvtk@users.noreply.github.com>

components/dashboard/user-assets-summary.tsx

@@ -0,0 +1,40 @@
+import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
+import { formatNumber } from "@/lib/utils"
+
+export function UserAssetsSummary() {
+  // 这里应该从API获取实际数据
+  const stats = {
+    totalUsers: 125689,
+    activeUsers: 78452,
+    highValueUsers: 12458,
+    conversionRate: 12.5,
+  }
+
+  return (
+    <Card className="border shadow-sm">
+      <CardHeader className="pb-2">
+        <CardTitle className="text-base font-medium">用户资产概览</CardTitle>
+      </CardHeader>
+      <CardContent>
+        <div className="grid grid-cols-2 gap-4">
+          <div className="space-y-1">
+            <p className="text-xs text-muted-foreground">总用户数</p>
+            <p className="text-2xl font-bold">{formatNumber(stats.totalUsers)}</p>
+          </div>
+          <div className="space-y-1">
+            <p className="text-xs text-muted-foreground">活跃用户</p>
+            <p className="text-2xl font-bold">{formatNumber(stats.activeUsers)}</p>
+          </div>
+          <div className="space-y-1">
+            <p className="text-xs text-muted-foreground">高价值用户</p>
+            <p className="text-2xl font-bold">{formatNumber(stats.highValueUsers)}</p>
+          </div>
+          <div className="space-y-1">
+            <p className="text-xs text-muted-foreground">转化率</p>
+            <p className="text-2xl font-bold">{stats.conversionRate}%</p>
+          </div>
+        </div>
+      </CardContent>
+    </Card>
+  )
+}