Watch for webview changes to avoid manual building

[dotNomad]

Right now whenever we make an update to a webview we need to do a npm run build on that project, and re-launch the VSCode extension debugger.

We could potentially use compound tasks to run both the vite --watch and the esbuild --watch at the same time so this is no longer necessary.

https://code.visualstudio.com/docs/editor/tasks#_compound-tasks

[mmarchetti]

For now, let's document dev workflows that are known to work.