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

server/src/libreoffice/libreoffice.interface.ts

@@ -0,0 +1,26 @@
+/**
+ * LibreOffice Service Interface Definition
+ */
+
+export interface LibreOfficeConvertResponse {
+  pdf_path?: string;
+  pdf_data?: string; // base64 encoded PDF data
+  converted: boolean;
+  original: string;
+  file_size: number;
+  error?: string;
+}
+
+export interface LibreOfficeHealthResponse {
+  status: string;
+  service: string;
+  version: string;
+  uptime: number;
+}
+
+export interface LibreOfficeVersionResponse {
+  service: string;
+  version: string;
+  framework: string;
+  libreoffice: string;
+}