v0.2.0

• Added guarded release-preparation automation that tags the exact merged
  commit, publishes it to pub.dev, and creates the matching GitHub Release.
• Added compatibility with Genkit 0.15, GenUI 0.10, and the extracted
  a2ui_core message types.
• Upgraded the hybrid and backend examples to genkit_llamadart 1.4.0 and the
  current compatible Genkit, provider, server, llamadart, and GenUI packages.
• Raised the hybrid example's macOS deployment target to 14.0, adopted
  Flutter's Swift Package Manager integration, and made its macOS integration
  smoke run automatically for relevant pull requests and pushes to main.
• Moved the opt-in LiteRT-LM device smoke and GenUI benchmark out of
  integration_test so default integration runs do not launch their
  heavyweight targets.