Research standard test result formats for better tooling integration

## Summary

Currently we use a custom verbose format for test results in the measure tool. We should research existing standard formats that might allow us to reuse existing tooling for reports and visualization.

## Current State

Our measure tool outputs verbose test results:
```
Running test: deposit_with_buyer_signature
✗ FAIL
Running test: deposit_missing_buyer_signature
✓ PASS
```

## Research Areas

1. **TAP (Test Anything Protocol)** - Simple text-based interface
2. **JUnit XML** - XML format widely supported by CI/CD tools
3. **JSON Test Results** - Machine-readable format for custom tooling
4. **GitHub Actions Test Results** - Integration with GitHub UI
5. **Other formats** used by testing frameworks

## Benefits

- **Reuse existing tools**: Test report generators, CI integrations, web dashboards
- **Better IDE integration**: Many IDEs understand standard formats
- **Ecosystem compatibility**: Works with existing testing infrastructure
- **Reduced maintenance**: Less custom parsing code in our scripts

## Implementation Plan

1. Research popular formats and their tooling ecosystems
2. Pick 1-2 formats that best fit our needs
3. Add format options to measure tool (`--format=tap`, `--format=junit`, etc.)
4. Update scripts to use standard formats
5. Evaluate available tooling for reports and visualization

## Related

This complements the short-term work in implementing a compact custom format for immediate script parsing improvements.