feat: create MobilePerformanceMonitor base structure

e2e/src/utils/MobilePerformanceMonitor.ts

@@ -0,0 +1,18 @@
+import { Page } from '@playwright/test';
+
+export interface CoreWebVitals {
+  FCP: number;
+  LCP: number;
+  CLS: number;
+  FID: number;
+  TTI: number;
+}
+
+export interface LighthouseResult {
+  score: number;
+  audits: Record<string, any>;
+}
+
+export class MobilePerformanceMonitor {
+  constructor(private page: Page) {}
+}