Report errors during parsing stage

[Emyrk]

Parsing errors are logged via slog.Logger

preview/preview.go

Lines 32 to 33 in 26db550

	slog.SetLogLoggerLevel(slog.LevelDebug)
	slog.SetDefault(slog.New(log.NewHandler(os.Stderr, nil)))

This needs to be corrected to not use the global logger. These warnings/errors should be silenced at worst, and reported at best via diagnostics.