feat: add admin site config page and optimize my page

Add "Site Configuration" page and refactor "My" page
Expand store with site, menu, and page configurations.

#VERCEL_SKIP

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

app/admin/site/loading.tsx

@@ -0,0 +1,14 @@
+export default function Loading() {
+  return (
+    <div className="p-8 max-w-4xl mx-auto">
+      <div className="animate-pulse">
+        <div className="h-8 bg-gray-700 rounded w-1/4 mb-8" />
+        <div className="space-y-6">
+          <div className="h-64 bg-[#0f2137] rounded-xl" />
+          <div className="h-48 bg-[#0f2137] rounded-xl" />
+          <div className="h-64 bg-[#0f2137] rounded-xl" />
+        </div>
+      </div>
+    </div>
+  )
+}