Allow use of builtin node WebSocket when available

[sbc100]

Node v21 and up have native WebSocket support. This change makes the import of the external ws module conditional so it will only run on older versions of node.

See #26676

[sbc100]

@jeroen

[jeroen]

Actually Claude suggests we also need to update the event handlers, see the second half of changes in libsockfs.js here: https://github.com/jeroen/emscripten/pull/1/changes

Because peer.socket.on('open', handleOpen) only applies to the ws implementation we no longer condition that on if (ENVIRONMENT_IS_NODE) but instead on if (typeof peer.socket.on === 'function') .

[sbc100]

Actually Claude suggests we also need to update the event handlers, see the second half of changes in libsockfs.js here: https://github.com/jeroen/emscripten/pull/1/changes

Because peer.socket.on('open', handleOpen) only applies to the ws implementation we no longer condition that on if (ENVIRONMENT_IS_NODE) but instead on if (typeof peer.socket.on === 'function') .

Good point. I decided to cleanup that code a bit first: #26683