feat: add validation for Revolut profile name format

- Add ownerRevolutProfileName field validation when enableRevolutPayment is true
- Validate profile name must start with '@' and contain only letters and numbers
- Add required field validation for Revolut profile name
- Add English and Croatian error messages for validation failures
- Update State type to include ownerRevolutProfileName errors

Validation regex: /^@[a-zA-Z0-9]+$/
Valid examples: @john123, @ivan, @user2024

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

messages/en.json

@@ -232,6 +232,8 @@
       "owner-iban-required": "Valid IBAN is mandatory",
       "owner-iban-invalid": "Invalid IBAN format. Please enter a valid IBAN",
       "currency-required": "Currency is mandatory",
+      "owner-revolut-profile-required": "Revolut profile name is mandatory",
+      "owner-revolut-profile-invalid": "Invalid Revolut profile format. Must start with '@' and contain only English letters and numbers (e.g., '@john123')",
       "validation-failed": "Validation failed. Please check the form and try again."
     }
   }