fix(S21/T01): fix all lint warnings and upgrade wsl to wsl_v5

Files:
- .golangci.yml
- backend/events/cmd/genevents/main.go
- backend/fileutil/atomicwrite_test.go
- backend/library/library.go
- backend/player/buffered_streamer_test.go
- backend/player/player.go
- backend/tagwriter/dbsync.go
- backend/tagwriter/mp3_test.go
- backend/tagwriter/ogg.go
- backend/tagwriter/ogg_test.go
- backend/tagwriter/ogg_vorbis.go
- backend/tagwriter/pipeline.go
- backend/tagwriter/tagwriter.go
- backend/tagwriter/wav_test.go

backend/fileutil/atomicwrite_test.go

@@ -261,6 +261,7 @@ func TestAtomicWrite_SyncAndClose(t *testing.T) {
 
 	// Write 1 MiB of data.
 	const size = 1 << 20 //nolint:mnd
+
 	data := bytes.Repeat([]byte("x"), size)
 
 	err := AtomicWrite(slog.Default(), target, func(tmp *os.File) error {