refactor: improve type safety by making 'next' optional in async route handlers and updating type imports

src/services/aiApiClient.test.ts

@@ -7,7 +7,6 @@ import { http, HttpResponse } from 'msw';
 vi.unmock('./aiApiClient');
 
 import * as aiApiClient from './aiApiClient';
-import { FlyerItem } from '../types';
 
 // 1. Mock logger to keep output clean
 vi.mock('./logger', () => ({
@@ -40,7 +39,7 @@ const server = setupServer(
     if (contentType?.includes('application/json')) {
       try {
         body = await request.json() as Record<string, unknown>;
-      } catch (err) { /* ignore parse error */ }
+      } catch { /* ignore parse error */ }
     } else if (contentType?.includes('multipart/form-data')) {
       try {
         // This is the key part. We read the formData from the request.
@@ -53,7 +52,7 @@ const server = setupServer(
         }
         formDataBody._isFormData = true;
         body = formDataBody;
-      } catch (err) { /* ignore parse error */ }
+      } catch { /* ignore parse error */ }
     }
 
     requestSpy({