feat: feat-v0.9.0

[Thegaram]

What changed

v0.9.0 changes which contract is deployed, not just versions. v0.8.0 deployed the flat Halo2Verifier. v0.9.0 deploys OpenVmHalo2Verifier, a wrapper that inherits it. The source moves from openvm-solidity-sdk@v1.6 to v2.0-deferral
(Scroll's bundle circuit defers proof verification).

• Bump OpenVM to v2.0.0, stark-backend to v2.0.0, snark-verifier-sdk to git v0.2.6, scroll-zkvm-verifier to v0.9.0.
• Drop openvm-native-recursion (removed in OpenVM v2.0.0) and the halo2-axiom feature (removed in snark-verifier-sdk@v0.2.6).
• Swap the openvm-sdk evm-prove feature for evm-verify, which subsumes it
• Compile the three verifier sources with solc --standard-json. snark-verifier's compile_solidity reads one source from stdin, so it cannot resolve the wrapper's imports
• Re-compute now uses Sdk::builder() with DeferralHookCommits, mirroring openvm-solidity-sdk's own generate-verifier
• Bump the toolchain to nightly-2025-11-20. The new dependencies need Rust 1.91.1 or newer
• Remove the forge fmt step and the Foundry v1.5.0 requirement. The SDK generator now emits canonical text

Why the solc settings matter

solc embeds a metadata hash that covers the source unit names and the compiler settings. Both modes therefore use the SDK's exact paths (src/v2.0-deferral/...) and settings: optimizer on with 100000 runs, constantOptimizer and the Yul optimizer off, evmVersion paris, and the forge-std/ remapping. Any change alters the codehash even when the executable code is identical.

Verification

generate-verifier and compute-digest both reproduce the deployed mainnet values exactly:

• codehash 0x00dfb6855747412fa70b8a75aaa4950f1deafaace9d2a4e9923ad2e1a3589928 matches the plonkVerifier at 0x0d2A59fd7060460F07c30C2817b4E79576da01C6
• digest-1 / digest-2 match verifierDigest1() / verifierDigest2() on the ZkEvmVerifierPostFeynman at 0x7966FE0De13e3B81533470640Ac489223476B254

cargo build, cargo clippy and cargo fmt --check are clean.

Not verified

--recompute is untested. It needs roughly 200 GB of RAM. Please run it on a large instance before merging.

Note for reviewers

Do not regenerate Cargo.lock from scratch. That drifts alloy-consensus from 1.1.2 to 1.8.3, whose CryptoProvider trait gains a required method that zkvm-prover v0.9.0 does not implement, and the build then fails in a dependency.