fn changed_favorite_ids(
cached: &HashSet<String>,
server: &HashSet<String>,
) -> Vec<String>Expand description
Ids whose favourite state differs between what we showed and what the server has — favourited elsewhere since the cache was written, or un-favourited elsewhere.
Pulled out of the command so the “emit nothing when nothing changed” rule is testable: an unchanged set must leave a quiet page quiet rather than triggering a refetch on every visit.
TRACES: UR-069 | DR-120 | UT-107