feat: type improvements: typeof fetch -> FetchEsque

[KATT]

Thanks! LGTM. Just a few linting issues, not sure if you care about those. But solution wise, I think it's a good direction!

One other thing I'd like to see is fetch-compatible interface being tRPC-driven, rather than typeof fetch. Maybe I can take a stub at this?

Originally posted by @moltar in #2723 (review)

• typeof fetch -> FetchEsque
• typeof AbortController -> AbortControllerEsque
• Tests for different fetch-implementations
• Response --> ??? (TBD)

[KATT]

I actually spent a few minutes on this here, @moltar, then I realised we had some global use of Response as extra contextual meta data when we call procedures

[mmkal]

When defining this type/interface might make sense to add some expect-type tests to make sure builtin-fetch, node-fetch, isomorphic-fetch, undici-fetch, deno-fetch all are type-compatible with it. Not sure if there are other widely used implementations? Edit: those might all already share a builtin typescript interface too, not sure.