feat(admin/problemset): add problem list table with Prisma query

src/app/(app)/dashboard/@admin/problemset/page.tsx

@@ -0,0 +1,19 @@
+import prisma from "@/lib/prisma";
+import { ProblemsetTable } from "@/components/features/dashboard/admin/problemset/table";
+
+export default async function AdminDashboardProblemsetPage() {
+  const problems = await prisma.problem.findMany({
+    select: {
+      id: true,
+      displayId: true,
+      title: true,
+      difficulty: true,
+    },
+  });
+
+  return (
+    <div className="h-full px-4">
+      <ProblemsetTable data={problems} />
+    </div>
+  );
+}