Function defs_auto_mount_a_page 

pub fn defs_auto_mount_a_page(defs: &[Stmt<'_>]) -> bool

Whether defs auto-mounts a ## Page — the parser’s own inserted Mount <page>. arrange relocates into the test body, not a statement the test’s own body ever writes. A test against such a program drives a mounted page exactly as much as an explicit Mount in its body does; largo test’s cross-tier check (testrun.rs) uses this SAME signal for that reason, so the two cannot drift on what “this test drives a mounted page” means.