Use new REPL for wasm demo

[treyhunner]

Feature or enhancement

Proposal:

The WASM demo in Tools/wasm was very useful for getting a Python REPL setup working in my web app.

It would be wonderful if that demo could be updated to work with the new Python 3.13 REPL (pyrepl).
I believe this would require a change to the way the file streams are handled (stdin specifically) though I'm not currently certain how to make that change.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-124621: Emscripten: Add support for async input devices #136822
• gh-124621: Emscripten: Fix regression in use-after-close error handling #136837
• gh-124621: Emscripten: Support pyrepl in browser #136931
• [3.14] gh-124621: Emscripten: Add support for async input devices (GH-136822) #136935
• [3.14] gh-124621: Emscripten: Support pyrepl in browser (GH-136931) #136978
• [3.14] gh-124621: Emscripten: Support pyrepl in browser (GH-136931) #136988
• gh-124621: Emscripten: Fix __syscall_ioctl patch #136993
• gh-124621: Emscripten: Add smoke test for using pyrepl in Chrome #137004