fix(server,web): forward-fix CI lint + vitest failures

- gofmt -s on system.go, system_cron.go, api.go
- rename unused r → _ in 3 fetcher_test.go HTTP handlers
- TrackRow +queue test uses /add .* to queue/i (track-aware aria-label from #377)
- /library/artists page test mocks likes + tanstack-query (ArtistCard now embeds LikeButton)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/playlists/system.go

@@ -82,12 +82,12 @@ const systemMixLength = 25
 // JitterMagnitude is 0 because daily determinism comes from tieBreakHash;
 // any randomness would defeat the within-day stability invariant.
 var systemMixWeights = recommendation.ScoringWeights{
-	BaseWeight:      1.0,
-	LikeBoost:       2.0,
-	RecencyWeight:   1.0,
-	SkipPenalty:     2.0,
-	JitterMagnitude: 0.0,
-	ContextWeight:   0.5,
+	BaseWeight:       1.0,
+	LikeBoost:        2.0,
+	RecencyWeight:    1.0,
+	SkipPenalty:      2.0,
+	JitterMagnitude:  0.0,
+	ContextWeight:    0.5,
 	SimilarityWeight: 1.5,
 }
 

internal/playlists/system_cron.go

@@ -14,12 +14,12 @@ import (
 // goroutine. Caller passes a context that's cancelled on graceful shutdown.
 //
 // Lifecycle:
-//   1. Clear any stale in_flight=true rows from a previously crashed process
-//      (safe at startup: by definition, nothing is running yet).
-//   2. Run once at startup so users catch up after a server restart without
-//      waiting up to 24h.
-//   3. Tick every 24h; runOnce on each tick.
-//   4. Exit on context cancellation.
+//  1. Clear any stale in_flight=true rows from a previously crashed process
+//     (safe at startup: by definition, nothing is running yet).
+//  2. Run once at startup so users catch up after a server restart without
+//     waiting up to 24h.
+//  3. Tick every 24h; runOnce on each tick.
+//  4. Exit on context cancellation.
 //
 // Per-user errors are logged but don't halt the loop. Per-cycle errors (e.g.,
 // "list active users" failed) are logged but the next tick still fires.