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/api/api.go

@@ -29,15 +29,15 @@ func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playev
 	rng := rand.New(rand.NewSource(rand.Int63()))
 	h := &handlers{
 		pool: pool, logger: logger, events: events, recCfg: recCfg,
-		rng:                rng.Float64,
-		lidarrCfg:          lidarrCfg,
-		lidarrRequests:     lidarrReqs,
-		lidarrQuarantine:   lidarrQuar,
-		tracks:             tracksSvc,
-		playlists:          playlistsSvc,
-		coverart:           coverEnricher,
+		rng:                 rng.Float64,
+		lidarrCfg:           lidarrCfg,
+		lidarrRequests:      lidarrReqs,
+		lidarrQuarantine:    lidarrQuar,
+		tracks:              tracksSvc,
+		playlists:           playlistsSvc,
+		coverart:            coverEnricher,
 		coverArtBackfillCap: coverBackfillCap,
-		dataDir:            dataDir,
+		dataDir:             dataDir,
 	}
 
 	r.Route("/api", func(api chi.Router) {