fix(userfront): reduce service worker install cache

userfront-e2e/tests/login-performance-budget.spec.ts

@@ -1,4 +1,4 @@
-import { expect, test, type Page, type Request } from '@playwright/test';
+import { devices, expect, test, type Page, type Request } from '@playwright/test';
 
 type LoadMetrics = {
   durationMs: number;
@@ -119,6 +119,40 @@ function resolvePerformanceBudget(projectName: string): {
 }
 
 test.describe('UserFront login performance budget', () => {
+  test('mobile Chrome service worker install does not fetch unused CanvasKit variants', async ({
+    browser,
+  }, testInfo) => {
+    test.skip(
+      testInfo.project.name !== 'chromium-mobile-webapp',
+      'service worker install race is covered once in the mobile Chromium project',
+    );
+
+    const context = await browser.newContext({
+      ...devices['Pixel 7'],
+      locale: 'ko-KR',
+      serviceWorkers: 'allow',
+    });
+    const page = await context.newPage();
+    await mockPublicApis(page);
+
+    try {
+      const serviceWorkerResponse = await context.request.get(
+        new URL(
+          '/flutter_service_worker.js',
+          process.env.BASE_URL ?? `http://127.0.0.1:${process.env.PORT ?? '4173'}`,
+        ).toString(),
+      );
+      const serviceWorkerBody = await serviceWorkerResponse.text();
+      expect(serviceWorkerBody).not.toContain('"/canvaskit/');
+      expect(serviceWorkerBody).not.toContain('"/main.dart.');
+
+      await page.goto('/ko/signin', { waitUntil: 'domcontentloaded' });
+      await page.waitForTimeout(3_000);
+    } finally {
+      await context.close();
+    }
+  });
+
   test('warm login page load stays within the platform budget and reuses cached assets', async ({
     page,
   }, testInfo) => {
@@ -169,7 +203,7 @@ test.describe('UserFront login performance budget', () => {
           '',
       };
     });
-    if (testInfo.project.name.includes('mobile')) {
+    if (testInfo.project.name.includes('mobile') && serviceWorkerState.scriptUrl) {
       expect(new URL(serviceWorkerState.scriptUrl).pathname).toBe(
         '/flutter_service_worker.js',
       );