Create all shapes from center

[DallinYauney]

Many of Graphite's shapes are based at their center. For example: on a 100x100 artboard, making a circle with a transform of 50x50 will center the circle to the artboard. However, some shapes with this transform will instead have their initial vertex (often the top-left corner) in the artboard's center.

The shapes that I've found to position themselves in this way are:

• Grid
• QR Code
• Arrow
• Line

Screencast_20260825_223744.webm

I'm not aware of any cases where this distinction would be important, but it might be better to have them standardized on the same behavior nonetheless.

[Keavon]

Grid and QR Code are rectangular-ish and thus debatable, but I lean towards their current behavior. Line and Arrow behave as intended. Feel free to discuss this further but since it's likely not actionable I'll close it.

[DallinYauney]

I generally agree that line and arrow shouldn't be changed.

My reasoning for opening this issue is this:
Since QR Codes aren't a part of the shape dropdown anymore, I went to make one by creating a rectangle and swapping the node out for a QR Code, but noticed that it wasn't positioned the way I expected.