fix(website): resolve @opennextjs/cloudflare and test configuration issues

- Successfully installed @opennextjs/cloudflare v1.15.1
- Fixed Vitest configuration to exclude e2e tests
- Renamed e2e test files from .spec.ts to .e2e.ts to avoid Bun test runner conflicts
- Updated eslint.config.mjs and playwright.config.ts
- All tests passing: Vitest (1/1), Playwright (6/6)
- Production bundle size: ~5MB < 10MiB limit
- Marked TODO 0 complete in plan

website/playwright.config.ts

@@ -11,6 +11,7 @@ import { defineConfig, devices } from '@playwright/test';
  */
 export default defineConfig({
   testDir: './e2e',
+  testMatch: '**/*.e2e.ts',
   /* Run tests in files in parallel */
   fullyParallel: true,
   /* Fail the build on CI if you accidentally left test.only in the source code. */