drop the subtitle-languages setting, it never influenced extraction

analyzer removes every subtitle unconditionally (see case 'Subtitle' in
decideAction) and the pipeline extracts all of them to sidecars — the config
was purely informational and only subtitles.ts echoed it back as
'keepLanguages' for a subtitle-manager ui that doesn't exist yet. we'll
revive language preferences inside that manager when it ships.

removes: the settings card + ui state, POST /api/settings/subtitle-languages,
the config default, the SUBTITLE_LANGUAGES env mapping, AnalyzerConfig's
subtitleLanguages field, RescanConfig's subtitleLanguages field, every
caller site (scan.ts / execute.ts / review.ts), and the keepLanguages
surface in subtitles.ts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/api/execute.ts

@@ -71,7 +71,6 @@ async function refreshItemFromJellyfin(itemId: number): Promise<void> {
 		db,
 		fresh,
 		{
-			subtitleLanguages: parseLanguageList(cfg.subtitle_languages, ["eng", "deu", "spa"]),
 			audioLanguages: parseLanguageList(cfg.audio_languages, []),
 			radarr: radarrEnabled ? radarrCfg : null,
 			sonarr: sonarrEnabled ? sonarrCfg : null,