Meta Issue: Protogalaxy Support

Hi there 👋, thanks for this awesome project!

Is there any plan on implementing the in-circuit Protogalaxy verifier and decider? I am interested in picking up these if nobody is working on them. I understand that the major focus of this project is currently on Nova, but it would be much appreciated if I could have the chance to contribute to this project.

Please let me know if you have any thoughts 😄

---
Edit:

So let me use this issue for tracking my progress. As we aim to support multiple folding schemes, it will be beneficial if we can make some code reusable. Therefore, in addition to circuits for Protogalaxy, I am also planning to do some refactoring.

- [x] Use `Transcript` and `TranscriptVar` for all folding schemes (#94)
- [x] Protogalaxy verifier gadget (#95)
- [x] Circuit for Protogalaxy-based IVC
- [x] CycleFold (#120)
- [x] Connect Protogalaxy verifier with CycleFold (#123)
- [x] Decider
- [x] Implement `DeciderEthCircuit` (#145)
- [x] Implement `Decider` (#172)
- [ ] Circuit for Protogalaxy-based PCD
- [ ] Support for multi-instances folding
- [ ] Zero-knowledge ProtoGalaxy?
- [ ] Include blinding factors when committing to witnesses
- [ ] Investigate zero-knowledge layer for ProtoGalaxy