refactor(problems): migrate description and solution to feature-based structure

- Remove old parallel route implementations (@Description and @Solutions)
- Add new feature-based components for problem description and solution
  - Create content and panel components for both features
  - Implement skeleton loading states
  - Use cached data fetching
- Update MDX rendering and scroll area implementations

src/app/(app)/problems/[id]/@Description/layout.tsx

@@ -1,16 +0,0 @@
-import { Suspense } from "react";
-import { Loading } from "@/components/loading";
-
-interface DescriptionLayoutProps {
-  children: React.ReactNode;
-}
-
-export default function DescriptionLayout({ children }: DescriptionLayoutProps) {
-  return (
-    <div className="h-full flex flex-col border border-t-0 border-muted rounded-b-3xl bg-background">
-      <Suspense fallback={<Loading />}>
-        {children}
-      </Suspense>
-    </div>
-  );
-}

src/app/(app)/problems/[id]/@Description/page.tsx

@@ -1,42 +0,0 @@
-import prisma from "@/lib/prisma";
-import { notFound } from "next/navigation";
-import MdxPreview from "@/components/mdx-preview";
-import { ScrollArea } from "@/components/ui/scroll-area";
-import ProblemDescriptionFooter from "@/components/features/playground/problem/description/footer";
-
-interface DescriptionPageProps {
-  params: Promise<{ id: string }>;
-}
-
-export default async function DescriptionPage({ params }: DescriptionPageProps) {
-  const { id } = await params;
-
-  if (!id) {
-    return notFound();
-  }
-
-  const problem = await prisma.problem.findUnique({
-    where: { id },
-    select: {
-      title: true,
-      description: true,
-    },
-  });
-
-  if (!problem) {
-    return notFound();
-  }
-
-  return (
-    <>
-      <div className="relative flex-1">
-        <div className="absolute h-full w-full">
-          <ScrollArea className="h-full [&>[data-radix-scroll-area-viewport]>div:min-w-0 [&>[data-radix-scroll-area-viewport]>div]:!block bg-background">
-            <MdxPreview source={problem.description} className="p-4 md:p-6" />
-          </ScrollArea>
-        </div>
-      </div>
-      <ProblemDescriptionFooter title={problem.title} />
-    </>
-  );
-}

src/app/(app)/problems/[id]/@Solutions/layout.tsx

@@ -1,16 +0,0 @@
-import { Suspense } from "react";
-import { Loading } from "@/components/loading";
-
-interface SolutionsLayoutProps {
-  children: React.ReactNode;
-}
-
-export default async function SolutionsLayout({ children }: SolutionsLayoutProps) {
-  return (
-    <div className="flex flex-col h-full border border-t-0 border-muted rounded-b-3xl bg-background">
-      <Suspense fallback={<Loading />}>
-        {children}
-      </Suspense>
-    </div>
-  );
-}

src/app/(app)/problems/[id]/@Solutions/page.tsx

@@ -1,43 +0,0 @@
-import prisma from "@/lib/prisma";
-import { notFound } from "next/navigation";
-import MdxPreview from "@/components/mdx-preview";
-import { ScrollArea, ScrollBar } from "@/components/ui/scroll-area";
-import ProblemSolutionFooter from "@/components/features/playground/problem/solution/footer";
-
-interface SolutionsPageProps {
-  params: Promise<{ id: string }>;
-}
-
-export default async function SolutionsPage({ params }: SolutionsPageProps) {
-  const { id } = await params;
-
-  if (!id) {
-    return notFound();
-  }
-
-  const problem = await prisma.problem.findUnique({
-    where: { id },
-    select: {
-      title: true,
-      solution: true,
-    },
-  });
-
-  if (!problem) {
-    return notFound();
-  }
-
-  return (
-    <>
-      <div className="relative flex-1">
-        <div className="absolute h-full w-full">
-          <ScrollArea className="h-full [&>[data-radix-scroll-area-viewport]>div:min-w-0 [&>[data-radix-scroll-area-viewport]>div]:!block bg-background">
-            <MdxPreview source={problem.solution} className="p-4 md:p-6" />
-            <ScrollBar orientation="horizontal" />
-          </ScrollArea>
-        </div>
-      </div>
-      <ProblemSolutionFooter title={problem.title} />
-    </>
-  );
-}

src/features/problems/description/components/content.tsx

@@ -0,0 +1,56 @@
+import { getCachedProblem } from "@/lib/prisma";
+import { Skeleton } from "@/components/ui/skeleton";
+import { MdxRenderer } from "@/components/content/mdx-renderer";
+import { ScrollArea, ScrollBar } from "@/components/ui/scroll-area";
+
+interface DescriptionContentProps {
+  id: string;
+}
+
+const DescriptionContent = async ({ id }: DescriptionContentProps) => {
+  const problem = await getCachedProblem(id);
+
+  return (
+    <ScrollArea className="h-full">
+      <MdxRenderer
+        source={problem?.description ?? "description not found"}
+        className="p-4 md:p-6"
+      />
+      <ScrollBar orientation="horizontal" />
+    </ScrollArea>
+  );
+};
+
+const DescriptionContentSkeleton = () => {
+  return (
+    <div className="h-full flex flex-col p-4 md:p-6">
+      {/* Title skeleton */}
+      <Skeleton className="h-8 w-3/4 mb-6" />
+
+      {/* Content skeletons */}
+      <Skeleton className="h-4 w-full mb-4" />
+      <Skeleton className="h-4 w-5/6 mb-4" />
+      <Skeleton className="h-4 w-2/3 mb-4" />
+      <Skeleton className="h-4 w-full mb-4" />
+      <Skeleton className="h-4 w-4/5 mb-4" />
+
+      {/* Example section heading */}
+      <Skeleton className="h-6 w-1/4 mb-4 mt-8" />
+
+      {/* Example content */}
+      <Skeleton className="h-4 w-full mb-4" />
+      <Skeleton className="h-4 w-5/6 mb-4" />
+
+      {/* Code block skeleton */}
+      <div className="mb-6">
+        <Skeleton className="h-40 w-full rounded-md" />
+      </div>
+
+      {/* More content */}
+      <Skeleton className="h-4 w-full mb-4" />
+      <Skeleton className="h-4 w-3/4 mb-4" />
+    </div>
+  );
+};
+
+export { DescriptionContent, DescriptionContentSkeleton };

src/features/problems/description/components/panel.tsx

@@ -0,0 +1,25 @@
+import { Suspense } from "react";
+import {
+  DescriptionContent,
+  DescriptionContentSkeleton,
+} from "@/features/problems/description/components/content";
+
+interface DescriptionPanelProps {
+  id: string;
+}
+
+const DescriptionPanel = ({ id }: DescriptionPanelProps) => {
+  return (
+    <div className="h-full flex flex-col border border-t-0 border-muted rounded-b-3xl bg-background overflow-hidden">
+      <div className="relative flex-1">
+        <div className="absolute h-full w-full">
+          <Suspense fallback={<DescriptionContentSkeleton />}>
+            <DescriptionContent id={id} />
+          </Suspense>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+export { DescriptionPanel };

src/features/problems/solution/components/content.tsx

@@ -0,0 +1,56 @@
+import { getCachedProblem } from "@/lib/prisma";
+import { Skeleton } from "@/components/ui/skeleton";
+import { MdxRenderer } from "@/components/content/mdx-renderer";
+import { ScrollArea, ScrollBar } from "@/components/ui/scroll-area";
+
+interface SolutionContentProps {
+  id: string;
+}
+
+const SolutionContent = async ({ id }: SolutionContentProps) => {
+  const problem = await getCachedProblem(id);
+
+  return (
+    <ScrollArea className="h-full">
+      <MdxRenderer
+        source={problem?.solution ?? "solution not found"}
+        className="p-4 md:p-6"
+      />
+      <ScrollBar orientation="horizontal" />
+    </ScrollArea>
+  );
+};
+
+const SolutionContentSkeleton = () => {
+  return (
+    <div className="h-full flex flex-col p-4 md:p-6">
+      {/* Title skeleton */}
+      <Skeleton className="h-8 w-3/4 mb-6" />
+
+      {/* Content skeletons */}
+      <Skeleton className="h-4 w-full mb-4" />
+      <Skeleton className="h-4 w-5/6 mb-4" />
+      <Skeleton className="h-4 w-2/3 mb-4" />
+      <Skeleton className="h-4 w-full mb-4" />
+      <Skeleton className="h-4 w-4/5 mb-4" />
+
+      {/* Example section heading */}
+      <Skeleton className="h-6 w-1/4 mb-4 mt-8" />
+
+      {/* Example content */}
+      <Skeleton className="h-4 w-full mb-4" />
+      <Skeleton className="h-4 w-5/6 mb-4" />
+
+      {/* Code block skeleton */}
+      <div className="mb-6">
+        <Skeleton className="h-40 w-full rounded-md" />
+      </div>
+
+      {/* More content */}
+      <Skeleton className="h-4 w-full mb-4" />
+      <Skeleton className="h-4 w-3/4 mb-4" />
+    </div>
+  );
+};
+
+export { SolutionContent, SolutionContentSkeleton };

src/features/problems/solution/components/panel.tsx

@@ -0,0 +1,25 @@
+import { Suspense } from "react";
+import {
+  SolutionContent,
+  SolutionContentSkeleton,
+} from "@/features/problems/solution/components/content";
+
+interface SolutionPanelProps {
+  id: string;
+}
+
+const SolutionPanel = ({ id }: SolutionPanelProps) => {
+  return (
+    <div className="h-full flex flex-col border border-t-0 border-muted rounded-b-3xl bg-background overflow-hidden">
+      <div className="relative flex-1">
+        <div className="absolute h-full w-full">
+          <Suspense fallback={<SolutionContentSkeleton />}>
+            <SolutionContent id={id} />
+          </Suspense>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+export { SolutionPanel };