fix(libzkevm): zkvm_bls12_* and zkvm_ripemd160 to be spec conformant

[han0110]

Motivation

Crate libzkevm has a few places that are not eth-act/zkvm-standards conformant, this PR attempts to fix that.

Solution

• zkvm_bls12_g1_add, zkvm_bls12_g1_msm

  Use all zeros for point at infinity (was 0x40 flag of bls12_381). Reject coordinates with flag bits set.

• zkvm_bls12_g2_add, zkvm_bls12_g2_msm

  Same, plus Fp2 order is c0 || c1 (was c1 || c0).

• zkvm_bls12_pairing

  Skip pairs with a point at infinity as perf improvement.

• zkvm_bls12_map_fp2_to_g2

  Read Fp2 input as c0 || c1. Hardcode the image of u = 0 to work around a bls12_381 bug (its SWU emits an off-curve y = 0 point for u = 0, the only affected input, which cofactor clearing then collapses to infinity). Image derived from with py_ecc.

• zkvm_ripemd160

  Write the digest to the last 20 bytes.

Also update conformance tests, examples, and test vectors to the corrected encoding, and verified against the test suites of execution-specs@tests-zkevm@v0.4.1 (23264 fixtures).

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes