Function progress_digest 

pub fn progress_digest(
    cliban_key: &str,
    status: &str,
    plan_body: Option<&str>,
    activity: &[ActivityLogEntry],
) -> String

The body of the living progress comment: one comment per linked issue, rewritten in place on every push, so it always describes now.

Unlike progress_comment — which appends what changed since the last sync — this is a snapshot: plan progress, the last few issue log findings, the latest test status a finding carried, and a footer telling a human why the comment keeps changing under them.