The plex_people headshot cache can outlive its subjects — when a title leaves the
Plex library, cast/crew who appear in nothing else are orphaned. prune_orphan_people
deletes rows whose name no longer appears in ANY movie/show cast_names/directors,
run at the end of every plex_sync (best-effort; a jsonb_typeof='array' guard skips
scalar/null JSONB values). The filterable cast_names self-clean with their row;
this cleans the only per-person cache. Verified: an injected orphan is dropped, real
people kept. (Plex cast-explore S4)