Android emulator CI on GitHub Actions

Instrumentation tests take 40 minutes because the emulator runs in software.

Why it happens

Without /dev/kvm the emulator falls back to software rendering, which is roughly ten times slower.

What to change

1. Run on a runner that exposes KVM to the job
2. Cache the AVD snapshot so the emulator boots warm
3. Use a headless system image without Google Play services where possible
4. Shard instrumentation tests across several emulator instances

Android emulator on runnerhut

jobs:
  instrumentation:
    runs-on: runnerhut-8vcpu-ubuntu-2404
    steps:
      - uses: actions/checkout@v4
      - run: ls -l /dev/kvm
      - uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: 34
          arch: x86_64
          script: ./gradlew connectedDebugAndroidTest

The only runnerhut-specific line is `runs-on: runnerhut-8vcpu-ubuntu-2404`. Everything else is standard GitHub Actions — the same actions, the same secrets and the same permissions model you use today.