[FEAT] CommitmentRegistry: scope by (chainId, version)

[roeezolantz]

Summary

Stores FHE computation commitments by (chainId, version, handle) instead of (version, handle). Same handle bytes posted from different source chains are now independent commitments — eliminates cross-chain shadowing/collision when TN later looks up commitment integrity.

versionStatus is also now per (chainId, version). Chains have independent crypto-material lifecycles; one chain rotating keys says nothing about another. Multiple Active versions per chain are allowed (rotation overlap window).

This is a fresh deploy of the v2 contract, not an upgrade of the existing one. The old contract's data was disposable and is left in place as orphaned storage.

API changes (breaking)

• postCommitments(uint64 chainId, bytes32 version, bytes32[] handles, bytes32[] commitHashes) — chainId is now first, uint64.
• postCommitmentsSafe(...) — same shape.
• setVersionStatus(uint64 chainId, bytes32 version, VersionStatus newStatus) — per-chain lifecycle.
• All view fns gain chainId as first arg: getCommitment, getSize, getHandleByIndex, getHandles, getVersionStatus.

Events

• CommitmentsPosted(uint64 indexed chainId, bytes32 indexed version, uint256 batchSize)
• CommitmentsPostedSafe(uint64 indexed chainId, bytes32 indexed version, uint256 newlyPosted, uint256 skipped)
• CommitmentMismatchSkipped(uint64 indexed chainId, bytes32 indexed version, bytes32 indexed handle, bytes32 stored, bytes32 attempted) — new; surfaces silent commitment drift in postCommitmentsSafe when a re-post has a different commitHash than what was stored. Strictly-equal redeliveries stay silent.
• VersionStatusChanged(uint64 indexed chainId, bytes32 indexed version, VersionStatus oldStatus, VersionStatus newStatus)

Errors

• InvalidChainId — chainId == 0 rejected at every entry point as defense-in-depth.
• VersionNotActive(uint64 chainId, bytes32 version), CommitmentAlreadyExists(uint64 chainId, bytes32 version, bytes32 handle), InvalidVersionTransition(uint64, bytes32, …) gain chainId.

Deploy script

scripts/deploy.ts now takes a CHAIN_IDS env var (comma-separated) and pre-activates INITIAL_VERSION (0x…02 to match fhe-engine's bumped COMMITMENT_VERSION) on each chain. Default for local devnet is 412346.

Tests

CommitmentRegistry.behavior.ts — 99 tests passing. Net additions over the v1 suite:

• 6 tests for cross-chain isolation (same handle on different chains is independent; getSize/getHandles don't leak; chainId == 0 rejected; chain B duplicate doesn't revert chain A's prior commitment).
• 3 tests for chainId == 0 rejection at each entry point (postCommitments, postCommitmentsSafe, setVersionStatus).
• 2 tests for CommitmentMismatchSkipped (emit on disagreement; stay silent on identical redelivery).
• Per-chain version lifecycle test (CHAIN_A's V1 deprecation doesn't touch CHAIN_B's V1).
• Multi-Active-per-chain rotation test.

Gas costs unchanged from v1: ~47K per commitment at scale.

Test plan

• pnpm compile clean
• pnpm test — 99 passing
• npx hardhat run scripts/estimateGasArbitrum.ts --network arbitrumSepolia (cosmetic — gas changed from v1 by <1%)

Companion PR

This is paired with the outer-repo PR that bumps the submodule pointer + updates the blockchain-poster + fhe-engine. That PR depends on this one landing first.