feat(glossary): add episode groups, search, and import/export

Apply glossary edits directly to translated subtitles and reload the active track. Keep terms with their originating episode, preserve existing translations, and clear stale episode groups with glossary entries.

src/mpv/mpvitem.cpp

@@ -324,6 +324,7 @@ void MpvItem::showTranslatedSubtitleFile(const QUrl &url, const QString &title)
     for (const QVariant &entry : std::as_const(m_subtitleTracks)) {
         const QVariantMap track = entry.toMap();
         if (track.value(QStringLiteral("externalFilename")).toString() == path) {
+            commandAsync(QStringList{QStringLiteral("sub-reload"), QString::number(track.value(QStringLiteral("id")).toInt())});
             showOnlySubtitle(track.value(QStringLiteral("id")).toInt());
             return;
         }