KSP plugin doesn't provide generated classes as a jar

[smocherla-brex]

Right now, the kt_ksp_plugin with kt_jvm_library produces an srcjar https://github.com/bazelbuild/rules_kotlin/blob/master/kotlin/internal/jvm/compile.bzl#L424 which can contain the generated Kotlin sources and the META-INF/ files. However, it doesn't include the generated .class files a processor may generate.

An example is illustrated in https://github.com/smocherla-brex/rules_kotlin-ksp-classes (Bazel 7, rules_kotlin 1.9.6, Kotlin 1.9) with Micronaut which generates .class files using ASM rather than .kt files with KSP. This means the final JAR won't have access to beans generated by KSP and will fail at runtime as illustrated as the created bean cannot be found.

To support this, it seems like an additional output jar can be created additionally with -ksp-kt-genclasses.jar and forward it downstream to other targets through JavaInfo so that it's available at runtime (or maybe add it to the existing src jar but colocating source files and class files seems odd)? I'd be happy to help contribute it if it makes sense.