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>

app/content/loading.tsx

@@ -0,0 +1,52 @@
+import { Skeleton } from "@/components/ui/skeleton"
+import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
+
+export default function ContentLoading() {
+  return (
+    <div className="container mx-auto p-4 space-y-6">
+      <div className="flex items-center justify-between mb-6">
+        <Skeleton className="h-10 w-64" />
+        <Skeleton className="h-10 w-32" />
+      </div>
+
+      <div className="grid grid-cols-1 md:grid-cols-3 gap-6 mb-6">
+        {Array(3)
+          .fill(0)
+          .map((_, i) => (
+            <Card key={i} className="shadow-sm">
+              <CardHeader className="pb-2">
+                <Skeleton className="h-6 w-32 mb-2" />
+              </CardHeader>
+              <CardContent>
+                <Skeleton className="h-16 w-full" />
+              </CardContent>
+            </Card>
+          ))}
+      </div>
+
+      <Card>
+        <CardHeader>
+          <CardTitle>
+            <Skeleton className="h-7 w-48" />
+          </CardTitle>
+        </CardHeader>
+        <CardContent>
+          <div className="space-y-4">
+            {Array(5)
+              .fill(0)
+              .map((_, i) => (
+                <div key={i} className="flex items-center gap-4">
+                  <Skeleton className="h-12 w-12 rounded-full" />
+                  <div className="space-y-2 flex-1">
+                    <Skeleton className="h-4 w-full" />
+                    <Skeleton className="h-4 w-3/4" />
+                  </div>
+                  <Skeleton className="h-8 w-24" />
+                </div>
+              ))}
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  )
+}