Massive backend refactoring done

tests/core-auth.spec.ts

@@ -50,6 +50,8 @@ test.describe('I. Core & Authentication', () => {
             }
 
             console.log('Failed to handle first login. Dumping page content...');
+            const fs = require('fs'); // Playwright runs in Node
+            await fs.writeFileSync('auth_failure.html', await page.content());
             console.log(await page.content());
             throw e;
         }