- Add sqflite_common_ffi + very_good_analysis; tighten analysis_options
- Add BackupService for JSON export/import of exercise state
- Add full test coverage: models, screens, services, widgets
- Add scripts/check_flutter_coverage.sh to enforce 100% line coverage
- Add docstrings to ExerciseState fields and storage service
- Minor fixes across screens, widgets, and sync/HTTP services
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VuiPt6GPWkxpLbJFrnfy8U
