Seventh admin page. Documents the disk-usage sort (hogs surface first),
the header totals, each column's meaning (orphaned = no subscribers,
usually a departed user's feed), and the three actions with their real
semantics: Refresh (manual poll vs. the Settings→Podcasts interval),
Delete files (resets episodes to pending, re-download on demand, and
the non-obvious part quoted: a refresh will not re-materialize them),
Remove (instance-wide: rows + files + everyone's subscriptions, unlike
a user's own unsubscribe). Cross-links the user podcast guide for the
listening side. Glossary gains Delete files and a scoped Remove.
