The ListenBrainz popularity API returns snake_case JSON fields
(recording_name, artist_name, total_listen_count, recording_mbid)
but LBTopRecording used camelCase JSON tags for Wails serialization.
All fields silently deserialized as zero values — empty strings and
zero counts — producing ~8000 blank rows in the top tracks section.
Fix: add lbTopRecordingWire with snake_case tags for API unmarshal,
convert to LBTopRecording (camelCase) for Wails. Cap results at 10
to avoid rendering thousands of rows for prolific artists.