feat: implement settings layout and navigation, add tag and thought pages with API integration

thoughts-frontend/app/thoughts/[thoughtId]/page.tsx

@@ -0,0 +1,85 @@
+import { cookies } from "next/headers";
+import {
+  getThoughtById,
+  getUserThoughts,
+  getUserProfile,
+  getMe,
+  Me,
+  Thought,
+} from "@/lib/api";
+import { buildThoughtThreads } from "@/lib/utils";
+import { ThoughtThread } from "@/components/thought-thread";
+import { notFound } from "next/navigation";
+
+interface ThoughtPageProps {
+  params: { thoughtId: string };
+}
+
+async function findConversationRoot(
+  startThought: Thought,
+  token: string | null
+): Promise<Thought> {
+  let currentThought = startThought;
+  while (currentThought.replyToId) {
+    const parentThought = await getThoughtById(
+      currentThought.replyToId,
+      token
+    ).catch(() => null);
+    if (!parentThought) break;
+    currentThought = parentThought;
+  }
+  return currentThought;
+}
+
+export default async function ThoughtPage({ params }: ThoughtPageProps) {
+  const { thoughtId } = params;
+  const token = (await cookies()).get("auth_token")?.value ?? null;
+
+  const initialThought = await getThoughtById(thoughtId, token).catch(
+    () => null
+  );
+
+  if (!initialThought) {
+    notFound();
+  }
+
+  const rootThought = await findConversationRoot(initialThought, token);
+
+  const [thoughtsResult, meResult] = await Promise.allSettled([
+    getUserThoughts(rootThought.authorUsername, token),
+    token ? getMe(token) : Promise.resolve(null),
+  ]);
+
+  if (thoughtsResult.status === "rejected") {
+    notFound();
+  }
+
+  const allThoughts = thoughtsResult.value.thoughts;
+  const me = meResult.status === "fulfilled" ? (meResult.value as Me) : null;
+
+  const author = await getUserProfile(rootThought.authorUsername, token).catch(
+    () => null
+  );
+  const authorDetails = new Map<string, { avatarUrl?: string | null }>();
+  if (author) {
+    authorDetails.set(author.username, { avatarUrl: author.avatarUrl });
+  }
+
+  const { repliesByParentId } = buildThoughtThreads(allThoughts);
+
+  return (
+    <div className="container mx-auto max-w-2xl p-4 sm:p-6">
+      <header className="my-6">
+        <h1 className="text-3xl font-bold">Conversation</h1>
+      </header>
+      <main>
+        <ThoughtThread
+          thought={rootThought}
+          repliesByParentId={repliesByParentId}
+          authorDetails={authorDetails}
+          currentUser={me}
+        />
+      </main>
+    </div>
+  );
+}