Evaluate migration to Kotlin Gradle binary compatibility validation

### Problem

We currently use a separate plugin for binary compatibility checks.

Kotlin Gradle Plugin provides built-in support for binary compatibility validation, which may simplify setup and reduce maintenance.

However, it is unclear:
- whether it fully covers our current use cases
- whether migration is feasible without regressions

### Expected

Evaluate whether Kotlin Gradle binary compatibility validation can replace the current solution.

### Acceptance criteria

- Compare current plugin vs Kotlin Gradle built-in solution
- Verify support for current use cases (public API checks, workflows)
- Decision made:
- migrate to Kotlin Gradle solution, or
- keep current plugin
- If migration is chosen:
- integration implemented
- existing checks continue to pass

### Motivation

Binary compatibility is critical for stable releases.

Using built-in tooling may:
- reduce maintenance overhead
- simplify build configuration
- improve consistency with Kotlin ecosystem :contentReference[oaicite:0]{index=0}

https://kotlinlang.org/docs/gradle-binary-compatibility-validation.html

We now use a separate plugin for this