chore: migrate ci to gh actions, bump dependencies

[vonovak]

Summary

• Migrate CI from CircleCI to GitHub Actions
• Update dependencies (React Native 0.83.3, Expo 55, detox 20.47, Gradle 9, etc.)

Details

CI Migration:

• Replace .circleci/config.yml with .github/workflows/test.yml
• 5 parallel jobs via matrix strategy: JS analysis, iOS e2e (old + new arch), Android e2e (old + new arch)
• Concurrency groups to cancel in-progress runs per branch/PR
• Caching for yarn, CocoaPods, and Gradle
• Artifacts uploaded on failure with 14-day retention
• Android emulator timezone set to Europe/Prague via adb root + setprop

Test plan

• green CI

Test Plan

What's required for testing (prerequisites)?

What are the steps to reproduce (after prerequisites)?

Compatibility

OS	Implemented
iOS	✅ ❌
Android	✅ ❌

Checklist

• I have tested this on a device and a simulator
• I added the documentation in README.md
• I updated the typed files (TS and Flow)
• I added a sample use of the API in the example project (example/App.js)
• I have added automated tests, either in JS or e2e tests, as applicable