Function standards_coverage 

pub fn standards_coverage(
    mission_id: &str,
    events: &[Event],
) -> Option<StandardsCoverage>

Fold one mission’s standards coverage matrix from its event slice. events may contain other missions’ events (filtered out, the provenance idiom). Pure and total: no clock, no filesystem, no git — a mission with no approved standards pin folds to None, and every render surface then emits nothing.

The pin source is the LATEST plan.approved carrying a standardsManifest — exactly the reducer’s authority (plan.revised never re-reads one, so neither does this fold; the two can never disagree about which manifest the mission consented to).