Fix nullable strings in kotlin

[vshcryabets]

No description provided.

[Copilot]

Pull request overview

This PR updates the Kotlin type-name generator to correctly support nullable strings (DataType.stringNullable) and adds a regression test, while also enabling the Foojay toolchain resolver in Gradle settings.

Changes:

• Add Foojay toolchain resolver convention plugin to settings.gradle.kts.
• Update GetTypeNameUseCase to map stringNullable to Kotlin String (with ? appended via canBeNull).
• Add a unit test to validate DataType.stringNullable renders as String?.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
settings.gradle.kts	Adds Foojay toolchain resolver plugin configuration.
cgen-lib/src/main/kotlin/generators/kotlin/GetTypeNameUseCase.kt	Extends the Kotlin type mapping to include stringNullable.
cgen-lib/src/test/java/generators/kotlin/GetTypeNameUseCaseTest.kt	Adds a test asserting nullable string maps to String?.

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[Copilot]

The when branch mixes a type-check (is DataType.string) with a value match (DataType.stringNullable) in the same condition list, which won’t compile. Since string/stringNullable are singleton objects, match them consistently (e.g., DataType.string, DataType.stringNullable -> "String"), or use is for both.

Suggested change

	is DataType.string, DataType.stringNullable -> "String"
	DataType.string, DataType.stringNullable -> "String"

[Copilot]

These helper fields are declared as public vals; in the existing tests in this package they’re typically private val to avoid leaking test internals and to align with JUnit test style in this codebase.

Suggested change

	val getArrayDataTypeUseCase = GetArrayDataTypeUseCase()
	val useCase = GetTypeNameUseCase(getArrayDataTypeUseCase)
	private val getArrayDataTypeUseCase = GetArrayDataTypeUseCase()
	private val useCase = GetTypeNameUseCase(getArrayDataTypeUseCase)

[Copilot]

To match the surrounding Kotlin tests in this module, consider using a static import (Assertions.assertEquals -> import org.junit.jupiter.api.Assertions.assertEquals) and calling assertEquals(...) directly for consistency.