build(android): migrate Kotlin compiler options

[Tinnci]

Draft status

This PR keeps the existing Kotlin Gradle Plugin application for current repository CI compatibility, while migrating deprecated Android kotlinOptions blocks to top-level kotlin { compilerOptions { ... } }.

This is intentionally not the full AGP 9 built-in Kotlin removal. Removing kotlin-android should be handled separately only when this repository is ready to require AGP 9 built-in Kotlin.

Scope

• battery_plus
• network_info_plus
• package_info_plus
• sensors_plus

No Dart APIs, Android manifests, SDK versions, or runtime code are changed.

Verification

• rg "kotlinOptions" on touched Android Gradle files returns no matches.
• rg "compilerOptions" confirms JVM target configuration exists.
• git diff --check

[Tinnci]

Closing this stale draft. The branch is blocked by previous failed/cancelled CI results and was not ready for review. Given the number of packages touched, this migration should be redone as a fresh, validated PR if it is still needed.