Make undo/redo multiplayer

[pbiggar]

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This article is a good discussion, and lots of the things they mention are things we do poorly or wrong. https://liveblocks.io/blog/how-to-build-undo-redo-in-a-multiplayer-environment

A good starting point would be a list of things we do wrong/badly.

Off the top of my head:

• we make a user undo through all canvas moves
• no animation on undo/redo
• users do not have separate undo/redo from other users
• there is no "debouncing" - eg if you type a string you have to undo through each step

[pbiggar]

• selection is not in the undo state
• neither is cursor position

[StachuDotNet]

Folding this into #5237 until it comes up again