Unify Halo2 examples

[sifnoc]

Problem

Currently, the Mopro project has multiple circuit implementations, each using a different repository. The halo2-fibonacci, hyperplonk-fibonacci, and gemini-fibonacci examples are separated and referenced independently in Cargo.toml.

This setup complicates maintenance and integration, especially as we try to unify features across these different backends.

Details

Currently, the Mopro project has multiple circuit implementations, each using a different repository.

The halo2-fibonacci, hyperplonk-fibonacci, and gemini-fibonacci examples are separated and referenced independently in Cargo.toml.

This setup complicates maintenance and integration, especially as we try to unify features across these different backends.

Acceptance criteria

• Migrate the halo2 example to "plonkish-circuits-sample" repository.
• Update the Cargo.toml to use the unified plonkish-circuits-sample for all backends.
• Verify that the circuit examples for all backends (HyperPlonk, Gemini, Plonk) are working correctly from the unified repository.

Next steps (optional)

Document the changes in the README or appropriate documentation file, specifying the consolidated repository for the circuit examples.

[sifnoc]

• [x] Use one example repo at https://github.com/zkmopro/mopro/pull/247
• [ ] Adding other circuit example in https://github.com/sifnoc/plonkish-fibonacci-sample