Support for Observable Plot's `utc` scale.

[Leftium]

Is your feature request related to a problem? Please describe.
I need support for scale type utc. It is very common to store/process dates in UTC time (Unix epochs).

Describe the solution you'd like
Support for utc scale like Observable Plot.

Describe alternatives you've considered

• Observable Plot
• Transform Unix timestamps (UTC) to conform to local time scale?

Additional context

• I thought I would try porting my Observable Plot plots to SveltePlot, but lack of UTC support may be a dealbreaker...

An error occurs when I try to port this code:

	const plotOptions = $derived({
		width: clientWidth,
		height,
		marginRight: MARGIN_RIGHT,
		marginLeft: MARGIN_LEFT,
		marginTop: 0,
		marginBottom: 0,
		y: { axis: null, domain: [yDomainTop, yDomainBottom], range: [0, height] },
		x: {
			type: 'utc',
			axis: xAxis ? true : null,
			domain: [msStart, msEnd],
			range: [MARGIN_LEFT, clientWidth - MARGIN_RIGHT],
			tickFormat: (ms: number) => nsWeatherData.tzFormat(ms, 'ha'),
		},
	});

No errors using time type scale, but the resulting days are misaligned:

• 12am June 16 should start at the very left.
• The cursor is currently over Jun 16 1am, but SveltePlot axis shows 11am June 15.
• (Showing KST data from CST timezone)

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The app is live here:

• https://weather-sense.leftium.com/
• https://github.com/Leftium/weather-sense/tree/main