fix: promote scroll containers to their own composite layers.

[sortedcord]

This PR fixes #54

I've applied will-change: transform to the scroll containers in tiling-area.tsx and kanban-area.tsx so it's explicitly instructing the browser to promote these elements to their own GPU compositor layers before interaction happens. This ensures scrolling runs entirely on the compositor thread and prevents expensive re-rasterization during UI navigation. And sure enough nodepad scrolls at 60 fps even on low end devices:

While this might not be very visible on systems made after 2020 or something it would however cause a decrease in cpu spike while using nodepad when scrolling with lots of nodes.

(As expected, barely any frames missing vsync deadlines)

[sortedcord]

I've figured out a few other areas where we can potentially gain performance like:

• Memoizing the ReactMarkdown component as right now, it re-renders on every parent render including hover state changes (the annotation re-renders on every keystroke right now)
• Replace transition-all with specific properties, for example with something like transition-[opacity,box-shadow,border-color] depending on what is needed

If you want I can include those changes as well in this PR.