[dajiaohuang]

Summary

• Discover ButtonStyleButton controls, including FilledButton, and report their enabled state.
• Discover CheckboxListTile and SwitchListTile with their labels and values; invoke their onChanged callbacks when pointer dispatch cannot reach them. Also support fallback callbacks for Checkbox and Switch.
• Preserve a wrapping Semantics.identifier in structured inspect results and classify these controls in semantic refs.
• Keep the packaged npm Dart SDK copy in sync.

Closes #68.

Validation

• Added a synthetic widget test for FilledButton, CheckboxListTile, and SwitchListTile discovery and fallback callbacks, including a Semantics identifier.
• Flutter 3.47.0: flutter test test/widget_interaction_fallback_test.dart — passed.
• git diff --check — passed.
• No real device, account, service, or app was used.