F6: coalesce whole-show/season Plex watch-pushes into ONE background task
(push_bulk_state_to_plex) that reuses a single DB session + keep-alive Plex
client, instead of scheduling one task (own session + HTTP client) per episode.
F8: cache a show's live Plex enrichment (metadata + related) per rating_key for
a short TTL and fetch the two calls in parallel; repeat opens skip the network.
Raw payloads are cached; per-user shaping stays out. An empty related list is not
cached (plex.related swallows a transient failure as [] — don't pin it for the TTL).
F10: remove dead code — the pre-unified /browse route + browse(), the /people
route + people() + _person_photo(), api.plexPeople, interface PlexPerson, and the
orphaned plex.people i18n block. DRY: appendPlexFilters() shared by plexLibrary +
plexFacets; one exported plexDetailUi.Filterable (was Fil + Filterable); PlexInfo
migrated onto the shared plexDetailUi hooks/menu (DetailCustomizeMenu gained
overlay + extra props; useDetailPrefs exposes savePref; PrefToggle exported).
Reviewed (high) → clean. F7 (facet aggregate collapse) deferred: self-exclusion
gives each sub-aggregate a distinct WHERE, and no measurement shows /facets slow.