The Top Shelf extension now fetches Continue Watching directly from
Plex/Jellyfin/Emby instead of replaying a cache the app wrote on its
last foreground Discover pass. The app publishes per-profile server
descriptors on every shelf sync (`updateSources`): token-free metadata
in the app group, tokens in an app-group-shared keychain item, both
wiped by `clear`. On success the extension rewrites the cached payload
as the offline fallback; any fetch failure falls back to the previous
cache-replay behavior. Poster images are passed as remote URLs, so the
extension no longer depends on app-side artwork downloads.
Episodes now render season/series poster art (2:3, `.poster` shape)
instead of 16:9 episode stills, and labels lead with the S/E marker so
long titles no longer hide it behind the focused-item marquee. Shelf
schema v3 (Dart, Android, tvOS envelopes bumped together) discards
stale wide-art caches instead of letterboxing them into poster slots.
close#1474close#1835
