feat(problem): add ProblemPage with DockView layout

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

@@ -0,0 +1,72 @@
+"use client";
+
+import {
+  Bot,
+  Code,
+  Description,
+  Solutions,
+  Submissions,
+  Testcase,
+  TestResult,
+} from "@/app/(app)/problems/[id]/features";
+import DockView from "@/components/dockview";
+
+export default function ProblemPage() {
+  return (
+    <DockView
+      storageKey="dockview:problem"
+      components={{
+        Description: () => <Description />,
+        Solutions: () => <Solutions />,
+        Submissions: () => <Submissions />,
+        Code: () => <Code />,
+        Testcase: () => <Testcase />,
+        TestResult: () => <TestResult />,
+        Bot: () => <Bot />,
+      }}
+      options={[
+        {
+          id: "Description",
+          component: "Description",
+          title: "Description",
+        },
+        {
+          id: "Solutions",
+          component: "Solutions",
+          title: "Solutions",
+          position: { referencePanel: "Description", direction: "within" },
+        },
+        {
+          id: "Submissions",
+          component: "Submissions",
+          title: "Submissions",
+          position: { referencePanel: "Solutions", direction: "within" },
+        },
+        {
+          id: "Code",
+          component: "Code",
+          title: "Code",
+          position: { referencePanel: "Submissions", direction: "right" },
+        },
+        {
+          id: "Bot",
+          component: "Bot",
+          title: "Bot",
+          position: { referencePanel: "Code", direction: "right" },
+        },
+        {
+          id: "Testcase",
+          component: "Testcase",
+          title: "Testcase",
+          position: { referencePanel: "Code", direction: "below" },
+        },
+        {
+          id: "TestResult",
+          component: "TestResult",
+          title: "Test Result",
+          position: { referencePanel: "Testcase", direction: "within" },
+        },
+      ]}
+    />
+  );
+}