Add .env file and fix Playwright webServer command to run from correct directory

The Playwright tests were timing out because:
1. Missing .env file with DATABASE_URL configuration
2. webServer command was running from wrong directory

Changes:
- Created frontends/nextjs/.env with DATABASE_URL and DBAL configuration
- Updated e2e/playwright.config.ts to use npm --prefix for correct path resolution
- Verified dev server starts successfully and responds to requests
- Database operations confirmed working (Prisma adapters functioning correctly)

Test status: Tests can now connect to server, infrastructure is ready

Co-authored-by: johndoe6345789 <224850594+johndoe6345789@users.noreply.github.com>

e2e/playwright.config.ts

@@ -34,7 +34,7 @@ export default defineConfig({
 
   /* Run your local dev server before starting the tests */
   webServer: {
-    command: 'npm run db:generate && npm run dev',
+    command: 'npm --prefix ../frontends/nextjs run db:generate && npm --prefix ../frontends/nextjs run dev',
     url: 'http://localhost:3000',
     reuseExistingServer: !process.env.CI,
     timeout: 300 * 1000,