feat: snarks js binding for gnark

[smsunarto]

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Gnark currently doesn't have a clean way to client side proving since snarksjs is reliant on a different r1cs encoding than the one gnark has.

Describe the solution you'd like
A snarkjs-gnark binding would allow snarksjs to do proving and witness generation for gnark circuits.

Arkworks have something similar https://github.com/arkworks-rs/circom-compat

Describe alternatives you've considered
The hacky alternative is to compile gnark with tinygo, but other issues seems to have flagged performance and reliability issues.

[ivokub]

Yup, we have been thinking about having some internal IR which we can nicely transpile from/to other languages (circom, noir). Currently not a big priority though, for Linea we're using gnark end to end.

Imo I have seen some efforts now and then (I think there is Noir-to-gnark transpiler somewhere), but dunno how well maintained they are.