caveats:

• logs don't stream
• I haven't set up codemirror
• only script vals supported

everything else should be fully functional.

you can prefill the editor with

• code: https://easrng-playground.web.val.run/?code=console.log(1)
• a val: https://easrng-playground.web.val.run/?load=easrng/playground
• some other url: https://easrng-playground.web.val.run/?load=https://any/other/url