Complete Switch support across applicable targets

[dashersw]

Reuse the existing native switch implementation and close concrete target-support gaps.

Part of Gea UI Elements — Community Contributions.

Area: Extraction and target support

Scope and acceptance criteria

• Inventory checkbox/switch rendering and events on each applicable target.
• Preserve existing macOS behavior; document checkbox versus switch presentation and avoid duplicate implementations.
• Verify checked/disabled state, reactive updates, touch/keyboard activation, and emitted events on claimed targets.

Existing implementation to reuse

• core/packages/core/index.d.ts
• apple/packages/geastack-apple/targets/macos/main/macos_renderer.mm
• companion/examples/gea-companion/components/Content.tsx

ScrollView, Canvas, Image/GIF, CameraView, VirtualList, virtual keyboard, Label/Text, TextField, TextArea, and Button already exist. Reuse those facilities; this issue does not request rebuilding them.

Contribution requirements

• Follow the contribution contract Document the component contribution contract #2, shared theme work Define shared component theme tokens and interaction states #3, and interaction/accessibility guidance Define and verify keyboard, focus, and accessibility behavior #5.
• Include a runnable example and focused tests for the behaviors listed above.
• Document the public API, resource cleanup, and target scope; report actual validation results and limitations.
• Add the example and verified target status to the gallery tracked in Build the UI elements gallery and target-support matrix #4.