New Features:
- Added Command.globalErrors stream for reactive error monitoring
- Stream emits all globally-routed command errors
- Perfect for analytics, crash reporting, and UI notifications
- watch_it integration with registerStreamHandler

Improvements:
- Renamed ErrorHandler* classes to *ErrorFilter pattern
- Deprecated old names (removed in v10.0.0)
- Added deprecated_member_use_from_same_package: ignore to analysis_options.yaml
- Removed old docsite folder (docs now at flutter-it.dev)

Tests:
- Added tests for new ErrorFilter classes
- Added comprehensive tests for globalErrors stream
- All 36 tests passing

Documentation:
- Updated global_configuration.md with globalErrors section
- Updated error_handling.md with stream examples
- Updated README.md with link to stream docs