Function drive_main 

pub fn drive_main<'a>(
    defs: &[Stmt<'a>],
    drive_stmts: &[Stmt<'a>],
    interner: &Interner,
    types: &TypeRegistry,
    policies: &PolicyRegistry,
) -> Result<String, String>

## Main driving a page — the plain, non-sealed twin of Scenario::lowered_vm_trace. There is no test to seal a world for and no reference trace to hold against: compile.rs::vm_outcome hands over a program’s own definitions and its own driving script (its gate has already made sure drive_stmts is nothing but driving statements), and this drives them exactly as a ## Test drives its candidate tier — one statement at a time, through the session’s guarded door, settling after each — so a trapping turn recovers here and a typed fetch completes here, the same as they do under ## Test.