Function compile_program_package 

pub fn compile_program_package(
    package: PortablePackageSource,
    entry: &str,
    entry_kind: EntryKind,
) -> Result<ProgramArtifact, Vec<Diagnostic>>

Compile one source module into the current artifact shape. Imports are rejected here because only compile_program_package has a resolved closure to bind them against; this prevents a second, path-sensitive loader from appearing in the browser adapter.