70a5f64871
Adds nextTitles (array of up to 3 display strings) plus mirrored single nextTitle/nextArtist/nextTrackTitle/nextFile for the immediate next track. Drives the Music Box overlays' 3-up "coming next" lines without overlays needing to query MPD themselves. Reads MPD status.nextsong, walks playlistinfo for the next 3 indices, applies the existing _flatten_tag + display-string cascade. Fields are None / [] at end of queue. Backwards-compatible: overlays that don't read the new keys are unaffected.