fix(mixes): close three intent gaps found in the system-playlists audit

Three discovery-mix defects from the intent audit (Scribe note #1254),
all sharing the same root pattern — skips treated as non-events:

- Deep Cuts (#1257): eligibility counted only unskipped plays, so a
  track skipped twice with zero completed listens read as "barely
  heard" and kept being re-offered. Tracks with >=2 skips no longer
  qualify; a single accidental skip doesn't banish.

- Rediscover (#1258): a skip on a rediscover-sourced play — the user
  explicitly declining the resurfacing invitation — changed nothing,
  so declined tracks re-qualified the next day forever. Such tracks
  now sit out 90 days.

- On This Day (#1256): day-of-year distance used plain ABS, so
  Dec 28 vs Jan 3 read as 359 days apart and the window silently
  gutted itself for ~3 weeks around every New Year. Now circular
  (LEAST(d, 365-d)), anchored on the build-date parameter instead of
  now() so it's testable and consistent with the mix's daily
  determinism.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TsF3cNoKrqCYsU78cXC8U6

internal/db/dbq/system_mixes.sql.go

@@ -27,12 +27,20 @@ play_counts AS (
       FROM play_events
      WHERE user_id = $1 AND was_skipped = false
      GROUP BY track_id
+),
+skip_counts AS (
+    SELECT track_id, COUNT(*) AS c
+      FROM play_events
+     WHERE user_id = $1 AND was_skipped = true
+     GROUP BY track_id
 )
 SELECT t.id, t.album_id, t.artist_id
   FROM tracks t
   JOIN affinity_artists aa ON aa.artist_id = t.artist_id
   LEFT JOIN play_counts pc ON pc.track_id = t.id
+  LEFT JOIN skip_counts sc ON sc.track_id = t.id
  WHERE COALESCE(pc.c, 0) <= 2
+   AND COALESCE(sc.c, 0) < 2
    AND NOT EXISTS (
        SELECT 1 FROM lidarr_quarantine q
         WHERE q.user_id = $1 AND q.track_id = t.id
@@ -60,6 +68,11 @@ type ListDeepCutsTracksRow struct {
 // gives per-play variety on top.
 // #419 Deep Cuts: low-play tracks (<=2 plays) from artists the user
 // has liked OR played heavily (>=5 non-skip plays across the artist).
+// Tracks the user has skipped twice or more don't qualify (#1257):
+// eligibility used to count only unskipped plays, so the most actively
+// rejected tracks read as "barely heard" and kept being re-offered.
+// Threshold 2 so a single accidental skip doesn't banish a track;
+// passive-signal only (no dislike UI, rule #101).
 // $1 user_id, $2 date string.
 func (q *Queries) ListDeepCutsTracks(ctx context.Context, arg ListDeepCutsTracksParams) ([]ListDeepCutsTracksRow, error) {
 	rows, err := q.db.Query(ctx, listDeepCutsTracks, arg.UserID, arg.Column2)
@@ -203,7 +216,10 @@ WITH windowed AS (
       FROM play_events
      WHERE user_id = $1 AND was_skipped = false
        AND started_at < now() - interval '30 days'
-       AND ABS(EXTRACT(DOY FROM started_at) - EXTRACT(DOY FROM now())) <= 10
+       AND LEAST(
+           ABS(EXTRACT(DOY FROM started_at) - EXTRACT(DOY FROM $2::date)),
+           365 - ABS(EXTRACT(DOY FROM started_at) - EXTRACT(DOY FROM $2::date))
+       ) <= 10
      GROUP BY track_id
 )
 SELECT t.id, t.album_id, t.artist_id
@@ -235,6 +251,13 @@ type ListOnThisDayTracksRow struct {
 // and window ±7→±10 so it surfaces on a months-old library instead
 // of needing a full year of history; still skips cleanly (no rows →
 // no playlist) when there's no qualifying history yet.
+// Day-of-year distance is circular (#1256): plain ABS made Dec 28 vs
+// Jan 3 read as 359 days apart, silently gutting the window for ~3
+// weeks around every New Year — precisely when holiday nostalgia is
+// the point. LEAST(d, 365-d) wraps the boundary; leap-year drift of
+// ±1 is absorbed by the ±10 window. The build date ($2, already here
+// for the md5 rotation) anchors "today" instead of now() so the
+// window is testable and consistent with the mix's daily determinism.
 // $1 user_id, $2 date string.
 func (q *Queries) ListOnThisDayTracks(ctx context.Context, arg ListOnThisDayTracksParams) ([]ListOnThisDayTracksRow, error) {
 	rows, err := q.db.Query(ctx, listOnThisDayTracks, arg.UserID, arg.Column2)
@@ -272,6 +295,19 @@ SELECT t.id, t.album_id, t.artist_id
        SELECT 1 FROM lidarr_quarantine q
         WHERE q.user_id = $1 AND q.track_id = t.id
    )
+   -- Declined-resurfacing cooldown (#1258): a skip on a
+   -- rediscover-sourced play is the user explicitly saying "I've moved
+   -- on" to the exact invitation this mix extends — such tracks sit
+   -- out ~90 days instead of re-qualifying the next day. Passive
+   -- signal only (rule #101).
+   AND NOT EXISTS (
+       SELECT 1 FROM play_events rp
+        WHERE rp.user_id = $1
+          AND rp.track_id = t.id
+          AND rp.source = 'rediscover'
+          AND rp.was_skipped = true
+          AND rp.started_at > now() - interval '90 days'
+   )
  ORDER BY (s.last_at <= now() - interval '6 months') DESC,
           (s.c >= 5) DESC,
           s.c DESC, t.id

internal/db/queries/system_mixes.sql

@@ -8,6 +8,11 @@
 -- name: ListDeepCutsTracks :many
 -- #419 Deep Cuts: low-play tracks (<=2 plays) from artists the user
 -- has liked OR played heavily (>=5 non-skip plays across the artist).
+-- Tracks the user has skipped twice or more don't qualify (#1257):
+-- eligibility used to count only unskipped plays, so the most actively
+-- rejected tracks read as "barely heard" and kept being re-offered.
+-- Threshold 2 so a single accidental skip doesn't banish a track;
+-- passive-signal only (no dislike UI, rule #101).
 -- $1 user_id, $2 date string.
 WITH affinity_artists AS (
     SELECT artist_id FROM general_likes_artists WHERE user_id = $1
@@ -23,12 +28,20 @@ play_counts AS (
       FROM play_events
      WHERE user_id = $1 AND was_skipped = false
      GROUP BY track_id
+),
+skip_counts AS (
+    SELECT track_id, COUNT(*) AS c
+      FROM play_events
+     WHERE user_id = $1 AND was_skipped = true
+     GROUP BY track_id
 )
 SELECT t.id, t.album_id, t.artist_id
   FROM tracks t
   JOIN affinity_artists aa ON aa.artist_id = t.artist_id
   LEFT JOIN play_counts pc ON pc.track_id = t.id
+  LEFT JOIN skip_counts sc ON sc.track_id = t.id
  WHERE COALESCE(pc.c, 0) <= 2
+   AND COALESCE(sc.c, 0) < 2
    AND NOT EXISTS (
        SELECT 1 FROM lidarr_quarantine q
         WHERE q.user_id = $1 AND q.track_id = t.id
@@ -63,6 +76,19 @@ SELECT t.id, t.album_id, t.artist_id
        SELECT 1 FROM lidarr_quarantine q
         WHERE q.user_id = $1 AND q.track_id = t.id
    )
+   -- Declined-resurfacing cooldown (#1258): a skip on a
+   -- rediscover-sourced play is the user explicitly saying "I've moved
+   -- on" to the exact invitation this mix extends — such tracks sit
+   -- out ~90 days instead of re-qualifying the next day. Passive
+   -- signal only (rule #101).
+   AND NOT EXISTS (
+       SELECT 1 FROM play_events rp
+        WHERE rp.user_id = $1
+          AND rp.track_id = t.id
+          AND rp.source = 'rediscover'
+          AND rp.was_skipped = true
+          AND rp.started_at > now() - interval '90 days'
+   )
  ORDER BY (s.last_at <= now() - interval '6 months') DESC,
           (s.c >= 5) DESC,
           s.c DESC, t.id
@@ -103,13 +129,23 @@ SELECT t.id, t.album_id, t.artist_id
 -- and window ±7→±10 so it surfaces on a months-old library instead
 -- of needing a full year of history; still skips cleanly (no rows →
 -- no playlist) when there's no qualifying history yet.
+-- Day-of-year distance is circular (#1256): plain ABS made Dec 28 vs
+-- Jan 3 read as 359 days apart, silently gutting the window for ~3
+-- weeks around every New Year — precisely when holiday nostalgia is
+-- the point. LEAST(d, 365-d) wraps the boundary; leap-year drift of
+-- ±1 is absorbed by the ±10 window. The build date ($2, already here
+-- for the md5 rotation) anchors "today" instead of now() so the
+-- window is testable and consistent with the mix's daily determinism.
 -- $1 user_id, $2 date string.
 WITH windowed AS (
     SELECT track_id, COUNT(*) AS c
       FROM play_events
      WHERE user_id = $1 AND was_skipped = false
        AND started_at < now() - interval '30 days'
-       AND ABS(EXTRACT(DOY FROM started_at) - EXTRACT(DOY FROM now())) <= 10
+       AND LEAST(
+           ABS(EXTRACT(DOY FROM started_at) - EXTRACT(DOY FROM $2::date)),
+           365 - ABS(EXTRACT(DOY FROM started_at) - EXTRACT(DOY FROM $2::date))
+       ) <= 10
      GROUP BY track_id
 )
 SELECT t.id, t.album_id, t.artist_id