Function run_strict_vm 

pub fn run_strict_vm(source: &str) -> EngineOutcome

Run source STRICTLY on the bytecode VM. Identical pipeline to vm_outcome (same front-end, same oracle-range compile), with the strict contract: a program the VM cannot run — one that needs the async runtime, one that needs the scheduler driver, or one its compiler rejects — is a TYPED REFUSAL (engine_ran: None, error says why). The tree-walker is NEVER silently substituted.