refactor: improve error handling and response structure for getThreads API function

nest-front/src/pages/public/ForumPage.tsx

@@ -217,7 +217,7 @@ export default function ForumPage() {
       {!loading && !error && (
         filteredCategories.length === 0 ? (
           <div className="crt-box" style={{ padding: '2rem', textAlign: 'center', color: 'var(--color-text-muted)', fontFamily: 'var(--font-mono)' }}>
-            No results found for "{search}"
+            {search.trim() ? `No results found for "${search}"` : 'No forum categories available yet.'}
           </div>
         ) : (
           filteredCategories.map((cat) => (

nest-front/src/utils/api.ts

@@ -114,14 +114,26 @@ export const forumApi = {
   getCategories: () =>
     apiFetch<ForumCategory[]>('/forum/categories'),
 
-  getThreads: (params?: { categoryId?: string; page?: number; limit?: number }) => {
+  getThreads: async (params?: { categoryId?: string; page?: number; limit?: number }) => {
     const q = new URLSearchParams();
     if (params?.categoryId) q.set('categoryId', params.categoryId);
     q.set('page', String(params?.page ?? 1));
     q.set('limit', String(params?.limit ?? 100));
-    return apiFetch<{ data: ForumThread[]; total: number; page: number; pages: number }>(
+
-      `/forum/threads?${q}`
+    const result = await apiFetch<{
-    );
+      data?: ForumThread[];
+      threads?: ForumThread[];
+      total: number;
+      page: number;
+      pages: number;
+    }>(`/forum/threads?${q}`);
+
+    return {
+      data: result.data ?? result.threads ?? [],
+      total: result.total,
+      page: result.page,
+      pages: result.pages,
+    };
   },
 
   getThread: (id: string) =>