feat: add automated test cleanup infrastructure

- Add cleanup-tests.sh script for automated test reorganization
- Safely backup manual test files with timestamps in tests/.backup/
- Generate cleanup-report.json with migration metrics
- Validate test structure after cleanup
- Log detailed cleanup progress and results

Enables safe migration from manual to automated testing

tests/.backup/debug-email-validation.js.20250908-012049

@@ -0,0 +1,23 @@
+/* eslint-disable no-console */
+// Test the email validation in browser console
+console.log('Testing email validation for admin@localhost');
+
+const emailRegex = /^[^\s@]+@[^\s@]+(\.[^\s@]+|localhost)$/;
+const testEmail = 'admin@localhost';
+
+console.log('Email:', testEmail);
+console.log('Regex:', emailRegex.toString());
+console.log('Test result:', emailRegex.test(testEmail));
+
+// Let's also test step by step
+console.log('Parts breakdown:');
+console.log('- Has @ symbol:', testEmail.includes('@'));
+console.log('- Before @:', testEmail.split('@')[0]);
+console.log('- After @:', testEmail.split('@')[1]);
+console.log('- No spaces:', !/\s/.test(testEmail));
+
+// Let's test a simpler regex that should definitely work
+const simpleRegex = /^[^@\s]+@[^@\s]+$/;
+console.log('Simple regex test:', simpleRegex.test(testEmail));
+
+// Copy this code and paste it in the browser console when you get the validation error