feat(validator): implement API Validator integration

[teogor]

Description

This PR implements integration for the Kotlinx Binary Compatibility Validator, helping maintain public API stability.

Changes

• ApiValidatorUtils.kt: Created utility for applying the validator plugin.
• WindsPlugin.kt: Integrated configureApiValidator into the plugin lifecycle.

Usage

Enable the validator in your build.gradle.kts:

winds {
    features {
        apiValidator = true
    }
}

Verification

• Verified plugin application and task availability (./gradlew apiCheck).