Mirrors the website repo's setup: a source-based scan of app/src/main
(Kotlin) that reports to the self-hosted SonarQube server after merge,
never gating PRs.
Uses the existing SonarQube project key Runic-Gateway-Android-app (the
server rejects re-creating a case-variant key). Supersedes #18.
Co-Authored-By: Claude <noreply@anthropic.com>
