The devshell `gradle` now serialises local builds with flock and runs
them under `nice` with capped workers, so several agents building at
once queue instead of piling up daemons and compile workers and taking
the machine down. With CI/GITHUB_ACTIONS set it execs Gradle directly,
leaving CI untouched. Also shorten the Gradle daemon idle timeout so
idle daemons are reaped sooner.
replace the flutter project with a gradle/compose android app:
- nix flake dev shell (jdk21, android sdk 35, build-tools 37, gradle)
- material3 app with a placeholder screen
- roborazzi/robolectric screenshot tests with one golden
- carry over the existing launcher/notification assets
austinried