Support for Built-in Kotlin

[remingtonc]

Opening an issue to track, as this message popped on build.

WARNING: Your app uses the following plugins that apply Kotlin Gradle Plugin (KGP): flutter_gemma, flutter_timezone, large_file_handler, shared_preferences_android, url_launcher_android
Future versions of Flutter will fail to build if your app uses plugins that apply KGP.

Please check the changelogs of these plugins and upgrade to a version that supports Built-in Kotlin.
If no such version exists, report the issue to the plugin. If necessary, here is a guide on filing 
an issue against a plugin: https://docs.flutter.dev/release/breaking-changes/migrate-to-built-in-kotlin/for-app-developers#report-incompatible-kotlin-gradle-plugin-usage-to-plugin-authors

[Just2sire]

Same issue here:
WARNING: Your app uses the following plugins that apply Kotlin Gradle Plugin (KGP): flutter_gemma, flutter_gemma_mediapipe
Future versions of Flutter will fail to build if your app uses plugins that apply KGP.

Please check the changelogs of these plugins and upgrade to a version that supports Built-in Kotlin.
If no such version exists, report the issue to the plugin. If necessary, here is a guide on filing
an issue against a plugin: https://docs.flutter.dev/release/breaking-changes/migrate-to-built-in-kotlin/for-app-developers#report-incompatible-kotlin-gradle-plugin-usage-to-plugin-authors

If you are a plugin author, please migrate your plugin to Built-in Kotlin using this guide: https://docs.flutter.dev/release/breaking-changes/migrate-to-built-in-kotlin/for-plugin-authors

[DenisovAV]

Quick update: 1.2.2 (flutter_gemma) and 1.0.4 (flutter_gemma_mediapipe) fix the actual build break that the KGP migration introduced on AGP 9 (see #360) — the plugins now compile correctly whether or not android.builtInKotlin is enabled.

On the KGP warning itself: it's harmless on current Flutter (your build still succeeds). It can't fully go away yet — Flutter's AGP-9 tooling sets android.builtInKotlin=false by default, and any app with a plugin that applies KGP (url_launcher_android, shared_preferences_android, record_android, …) keeps the warning until Flutter flips built-in Kotlin to the default and those plugins migrate. So we intentionally still apply KGP when built-in Kotlin is off — dropping it would reintroduce #360. Keeping this issue open to track the full migration once the ecosystem is ready.