feat: add followers and following pages with API integration, enhance profile page with follower/following counts

thoughts-frontend/app/users/[username]/followers/page.tsx

@@ -0,0 +1,33 @@
+import { cookies } from "next/headers";
+import { notFound } from "next/navigation";
+import { getFollowersList } from "@/lib/api";
+import { UserListCard } from "@/components/user-list-card";
+
+interface FollowersPageProps {
+  params: { username: string };
+}
+
+export default async function FollowersPage({ params }: FollowersPageProps) {
+  const { username } = params;
+  const token = (await cookies()).get("auth_token")?.value ?? null;
+
+  const followersData = await getFollowersList(username, token).catch(
+    () => null
+  );
+
+  if (!followersData) {
+    notFound();
+  }
+
+  return (
+    <div className="container mx-auto max-w-2xl p-4 sm:p-6">
+      <header className="my-6">
+        <h1 className="text-3xl font-bold">Followers</h1>
+        <p className="text-muted-foreground">Users following @{username}.</p>
+      </header>
+      <main>
+        <UserListCard users={followersData.users} />
+      </main>
+    </div>
+  );
+}