feat: implement QuestionBank CRUD with pagination and template query

- Add pagination support to findAll (page, limit query params)
- Add findByTemplateId method to service
- Add GET /by-template/:templateId endpoint to controller
- Service already includes CRUD for QuestionBank and QuestionBankItem

web/services/pdfPreviewService.ts

@@ -0,0 +1,33 @@
+import { PDFStatus } from '../types';
+import { apiClient } from './apiClient';
+
+export const pdfPreviewService = {
+  
+  async getPDFUrl(fileId: string): Promise<{ url: string }> {
+    const { data } = await apiClient.get<{ url: string }>(`/knowledge-bases/${fileId}/pdf-url`);
+    return data;
+  },
+
+  
+  async getPDFStatus(fileId: string): Promise<PDFStatus> {
+    const { data } = await apiClient.get<PDFStatus>(`/knowledge-bases/${fileId}/pdf-status`);
+    return data;
+  },
+
+  
+  async preloadPDF(fileId: string, force: boolean = false): Promise<void> {
+    try {
+      const url = `/knowledge-bases/${fileId}/pdf-url` + (force ? '?force=true' : '');
+      const response = await apiClient.request(url, {
+        method: 'GET',
+        signal: AbortSignal.timeout(30000), // Increase timeout for conversion
+      });
+
+      if (response.ok) {
+        console.log('PDF already exists or conversion completed');
+      }
+    } catch (error: any) {
+      console.log('PDF conversion triggered:', error.message);
+    }
+  },
+};