Some issues around embedded StackBlitz

[3cp]

The StackBlitz's webcontainer doesn't work in Firefox and Safari when it's embedded (iframe).

The full StackBlitz web app (not embedded) does work in Safari and Firefox.

The issue for embedded probably needs to wait for StackBlitz themselves.

Two other issues can be solved:

• use vite, not webpack with StackBlitz.
• opened tabs didn't show all files.

For example, first example in playground only shows my-app.html, there is no way to open my-app.ts