

This would be a whole new pipeline to make interactivity work. Emulating a server with cached responses would allow to reuse the JS part of websites and is easier to do. I have no doubt that some pages wouldn’t work and there would be a shitton of security considerations I can’t imagine.
This is supported, but not integrated in bookmark lookup. I mean, if you hit ctrl+s, the browser will save currently rendered HTML. No crawling required. Hooking up some text indexing for search seems perfectly doable.