fix(ksp): preserve generic type args for suspend functions returning non-generic typealiases + fix server leak in tests

[Copilot]

KSP was losing concrete type arguments when a suspend function returned a non-generic typealias (e.g. typealias BarList = List<Bar>). Because the alias has no typeParameters, KSType.arguments was empty, causing Argument.of(List, "T") with a literal "T" instead of the resolved Bar — resulting in a ClassCastException at runtime.

Changes

• AbstractKotlinElement.kt: When resolving type arguments, detect a non-generic KSTypeAlias (one with no typeParameters) and expand to its underlying type before iterating arguments. This recovers the concrete type parameters (e.g. Bar) that would otherwise be invisible.

• SuspendClient.kt / SuspendClientController.kt: Add typealias BarList = List<Bar> and a /bars endpoint returning List<Bar> to exercise the fix.

• SuspendClientSpec.kt: Add regression test testSuspendClientReturnsTypealiasToList that calls getBars(): BarList and asserts the response is correctly deserialized. Additionally, wrap all tests in use { } blocks so the EmbeddedServer is always stopped after each test, preventing port/thread accumulation across the test JVM.

// Before — typealias return type loses its concrete argument
typealias BarList = List<Bar>

@Get("/bars")
suspend fun getBars(): BarList  // would fail with ClassCastException

// After — underlying type is resolved, Bar is correctly substituted