Function optimization_trace_jit 

pub fn optimization_trace_jit(
    source: &str,
    program_args: &[String],
) -> JitBackendOptimizationTrace

Execute through the production eager optimizer and a fresh private forge tier, returning both shared-pass and native-lowering evidence. Native refusals enter the common fallback channel as Jit -> Vm, so a missed tier can no longer hide behind a successful bytecode completion.