[feat] Added support for Bun

[mchao123]

Added support for Bun, added runtime selectors.

This is a tentative change that may require a review of the code.

[cexbrayat]

@mchao123 Thanks for the PR

@haoqunjiang Is this something we want to support as an option and yet another feature to maintain? Or could we just add a note in the README instead (as, IIUC, this just requires users to use a specific tsconfig file?).

[haoqunjiang]

@haoqunjiang Is this something we want to support as an option and yet another feature to maintain? Or could we just add a note in the README instead (as, IIUC, this just requires users to use a specific tsconfig file?).

I'm open to add bun support considering it's low-effort. But I don't think we need yet another option to show to every user. User-agent detection should suffice.