feat(db): add M6a home-section queries (recently added, most played, last played)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/db/queries/recommendation.sql

@@ -201,3 +201,55 @@ FROM contributions
 GROUP BY candidate_mbid, candidate_name
 ORDER BY total_score DESC
 LIMIT $3;
+
+-- name: ListMostPlayedTracksForUser :many
+-- M6a: top-N tracks by completed-play count for the user. was_skipped
+-- excludes skips so a user spamming next doesn't fabricate a top track.
+-- Quarantined tracks (per-user soft-hide from M5b) are filtered out.
+SELECT sqlc.embed(t),
+       albums.title AS album_title,
+       artists.name AS artist_name
+FROM tracks t
+JOIN albums  ON albums.id  = t.album_id
+JOIN artists ON artists.id = t.artist_id
+JOIN play_events pe ON pe.track_id = t.id
+WHERE pe.user_id = $1
+  AND pe.was_skipped = false
+  AND NOT EXISTS (
+      SELECT 1 FROM lidarr_quarantine q
+      WHERE q.user_id = $1 AND q.track_id = t.id
+  )
+GROUP BY t.id, t.title, t.album_id, t.artist_id, t.duration_ms, t.file_path,
+         t.file_format, t.file_size, t.bitrate, t.track_number, t.disc_number,
+         t.mbid, t.genre, t.added_at, t.updated_at,
+         albums.title, artists.name
+ORDER BY count(*) DESC, t.id
+LIMIT $2;
+
+-- name: ListLastPlayedArtistsForUser :many
+-- M6a: artists ranked by max(play_events.started_at) for the user, with
+-- a derived cover_album_id via a representative-album lateral join (most
+-- recent album that has cover_art_path set). album_count joined for the
+-- ArtistRef wire shape.
+SELECT sqlc.embed(a),
+       cov.id        AS cover_album_id,
+       cnt.album_count::bigint AS album_count,
+       max_started.started_at::timestamptz AS last_played_at
+FROM artists a
+JOIN LATERAL (
+    SELECT max(pe.started_at) AS started_at
+    FROM play_events pe
+    JOIN tracks t ON t.id = pe.track_id
+    WHERE pe.user_id = $1 AND t.artist_id = a.id
+) max_started ON max_started.started_at IS NOT NULL
+LEFT JOIN LATERAL (
+    SELECT id FROM albums
+    WHERE artist_id = a.id AND cover_art_path IS NOT NULL
+    ORDER BY created_at DESC LIMIT 1
+) cov ON true
+LEFT JOIN LATERAL (
+    SELECT count(*) AS album_count
+    FROM albums WHERE artist_id = a.id
+) cnt ON true
+ORDER BY max_started.started_at DESC, a.id
+LIMIT $2;