That's super cool! Not needing to install is great for accessibility for new users, and I think this would also be cool if it can be embedded into other websites as a viewer (like imagine opening up a Git repo with KiCAD files in it and being able to explore them in an integrated viewer)
That's a neat idea! To be honest my brain is overflowing with ideas too, right now I want to just bring all the apps one. Or... Actually just bring the layout editor up first :) I'm trying hard to live in the present...
There's already some work in that direction, too: https://github.com/theacodes/kicanvas