Function missing_blockers 

pub fn missing_blockers(
    queue: &Queue,
    questions: &Questions,
    blocked_by: &[String],
) -> Vec<String>

Ids inside a blocked_by list that name neither an existing task file nor an existing question file - a dependency deleted (magi task rm, or by hand) while something was still waiting on it.

Existence is decided by Queue::path_of/Questions::path_of is_file() alone, never by Queue::get/Questions::get succeeding: those also fail on a merely unreadable file - mid-write, corrupt, or from a schema ahead of this build (see [read_path]) - and misreading “cannot read it right now” as “it was deleted” would quarantine a task over a transient failure. blocked_by always carries a full id, written by crate::conduct or crate::triage from a real task’s or question’s own id/short, never a prefix a caller typed - so the exact-path check is complete on its own, with no Queue::resolve_id fallback needed.