fix(android): install camelCase flavor APKs from output-metadata.json - #2853

Summary

run-android --device / --list-devices / --interactive installs the outputFile named in AGP output-metadata.json instead of guessing a hyphenated filename from --mode. Gradle writes app-stagingInternal-debug.apk for a camelCase product flavor (for example stagingInternalDebug); the CLI looked for app-staging-internal-debug.apk because it derived the filename by splitting --mode on capitals and joining with hyphens. The output directory is already correct (apk/stagingInternal/debug); only the filename was wrong.

That split cannot be made correct for every project: acmeStagingDebug is either one flavor named acmeStaging or the flavors acme and staging, and those produce different filenames in the same directory. #2324 / #2762 already fixed the directory; the CLI still guessed the filename.

output-metadata.json is the file captured on AGP 8.13.0 in the issue, and later used successfully via a local patch on 20.2.0. ABI splits follow the device CPU list rather than metadata array order. The previous name guess remains as a fallback when the metadata file is missing or the listed APK is not on disk.

Decided: read output-metadata.json first, keep the existing guess as fallback. Alternative: try both the hyphenated and unsplit flavor names as candidate filenames. The two Gradle layouts cannot be told apart from --mode alone; the reporter already verified the metadata approach on 20.2.0 with --list-devices and --device. Can switch to the dual-candidate heuristic if that is preferred.

Fixes #2851

Test Plan

• Unit tests in packages/cli-platform-android/src/commands/runAndroid/__tests__/tryInstallAppOnDevice.test.ts:
  • camelCase flavor stagingInternalDebug installs app-stagingInternal-debug.apk from metadata
  • ABI splits follow device CPU preference, not metadata order
  • multi-dimension acmeStagingDebug still installs app-acme-staging-debug.apk when metadata is absent
  • still errors when no APK is present
• yarn test packages/cli-platform-android (5 suites, 21 tests)
• Optional, needs a device/emulator and a flavored app: add flavorDimensions 'env' / productFlavors { stagingInternal { dimension 'env' } }, then run-android --mode stagingInternalDebug --list-devices and confirm the APK in android/app/build/outputs/apk/stagingInternal/debug/ is installed. The same command without --list-devices already worked (Gradle install).

Checklist

• Documentation is up to date.
• Follows commit message convention described in CONTRIBUTING.md.
• For functional changes, my test plan has linked these CLI changes into a local react-native checkout. Filename selection is covered by the unit tests above; a linked checkout would only re-check the same install path against a real Gradle output.