Plex treats a subtitle stream as forced when its title says "Forced" even
with the API flag unset. Every forced comparison now uses that effective
forced-ness on both sides: the match scorer, the low-metadata hard gate,
the Jellyfin OnlyForced/Smart profile modes, and stream-index negotiation.
Carrying a track choice into the next episode no longer reuses the
same-item identity matchers. A sealed SubtitlePreference (off / track
reference / semantic intent) replaces the id-'navigation' pseudo-track
through the whole preference channel, and cross-item intents hard-require
language and forced-class parity. When the next episode has no track of
the same class, the intent declines and selection falls through to the
server's own per-episode choice instead of latching onto a full track by
position and persisting that mistake back to the server.
Intents wait for pending native tracks under the same catalog-completeness
rule as source ids, so an early decline cannot retire the selection
listener before the real track arrives.
Ref #1716
