Migrate all error messages to standardized PREFIX-NNN format: - EVT-001..007 (EventDecoder) - URI-001..009 (UriDecoder) - REG-001..040 (RegistrationValidator) - VAL-001..010 (Validation) 44 messages migrated, all test assertions updated.
Migrate all error messages to standardized PREFIX-NNN format:
44 messages migrated, all test assertions updated.