REPL: solo and sync configuration

[bthj]

Those changes are to open a configuration path through the @strudel/repl package to existing implementations for controlling whether multiple REPLs:

• play in sync
• and simultaneously

Relevant Discord message

[felixroos]

thanks for the PR! you need to run pnpm codeformat to fix the test

[bthj]

Thanks for the instructions @felixroos , I've updated the PR with changes made by pnpm codeformat

[felixroos]

thanks :)