feat(dead-code): add Kotlin grep verification support

[duriantaco]

Summary

• add Kotlin .kt / .kts detection to grep verification
• add Kotlin source globs and module candidates for src/main/kotlin and src/test/kotlin
• recognise Kotlin definition lines for functions, classes, objects, interfaces, and enum classes
• suppress Kotlin framework/test roots such as @Test, @Override, and @Composable

Tests

• pytest .