Fixes#711
When PHPUnit XML output contains <error> or <failure> elements without a
message attribute, the parser now extracts the error message from the error
details text instead of only showing the error type.
The improved logic:
1. Prefer message attribute when present (with type prepended)
2. Extract error message from details when it contains a line matching
the error type (e.g., "TypeError: ...")
3. Fall back to first line of details
4. Finally, use error type as last resort
This provides more informative error messages in test reports when
PHPUnit outputs errors with the full stack trace in the element text
rather than a message attribute.
