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/tenant/tenant.middleware.ts

@@ -0,0 +1,16 @@
+import { Injectable, NestMiddleware } from '@nestjs/common';
+import { Request, Response, NextFunction } from 'express';
+import { tenantStore } from './tenant.store';
+
+@Injectable()
+export class TenantMiddleware implements NestMiddleware {
+  use(req: Request, res: Response, next: NextFunction) {
+    const tenantId = req.headers['x-tenant-id'] as string;
+
+    // Wrap the execution in the tenant store context
+    // Initial values might be empty or partial until the AuthGuard validates them
+    tenantStore.run({ tenantId: tenantId || '' }, () => {
+      next();
+    });
+  }
+}