Release v2.3.0: TOML config migration + debug HTTP API

BREAKING CHANGE: Configuration format migrated from YAML to TOML

Features:
- TOML configuration format (probe.yaml → probe.toml)
- Debug HTTP API for troubleshooting (/debug/metrics endpoint)
- Enhanced bootstrap wizard with debug API configuration
- GPU debug logging for troubleshooting GPU metrics

Migration required for existing users - see CHANGELOG.md for guide.