Revert "Add missing admin action files and navigation links"

This reverts commit 41be6835bf.

src/app/admin/import/furni/loading.tsx

@@ -1,21 +0,0 @@
-import { Skeleton } from '@/components/ui/skeleton'
-
-export default function ImportFurniLoading() {
-  return (
-    <div className="space-y-6">
-      <div>
-        <Skeleton className="h-9 w-48" />
-        <Skeleton className="h-5 w-72 mt-2" />
-      </div>
-      <div className="rounded-lg border bg-card p-6 space-y-4">
-        {Array.from({ length: 6 }).map((_, i) => (
-          <div key={i} className="space-y-2">
-            <Skeleton className="h-4 w-24" />
-            <Skeleton className="h-10 w-full" />
-          </div>
-        ))}
-        <Skeleton className="h-10 w-24 mt-4" />
-      </div>
-    </div>
-  )
-}