Function intent_digest 

pub fn intent_digest(
    project: &Path,
    policy: &Policy,
    tasks_file: &str,
) -> String

SHA-256 over the intent files except the task lists (files named tasks_file, whose task lines the commits pin one by one with Task-Line:): what the verdict commits name (Intent-Digest:), so a later reader can tell the spec, plan or constitution changed — not a tick or a convergence round.