Add CODEOWNERS entries for new `zk/` and mainnet-ops paths

[Gbangbolaoluwagbemiga]

Overview

Add or update a CODEOWNERS file with entries for the new ZK-related paths (contracts/zk-verifier/, contracts/zk-rollup/, contracts/private-transfer/, ZK sections of tooling/sanctifier-core/src) and mainnet-ops-sensitive paths (deploy scripts, workflows), so PRs touching these high-stakes areas automatically request review from the right people.

Background / Context

Given the security-critical nature of both the ZK cryptographic code and mainnet deployment tooling introduced this wave, ensuring the right reviewers are automatically requested reduces the risk of an under-reviewed change slipping through, complementing the branch-protection rules in BRANCH_PROTECTION.md.

Goal

A CODEOWNERS file (or updated existing one) with entries covering the new ZK and mainnet-ops paths, verified to correctly auto-request review on a test PR.

Scope of Work

1. Add/update CODEOWNERS with entries for contracts/zk-*/, ZK-related core engine paths, scripts/deploy*.sh, and mainnet-specific workflow files.
2. Verify auto-review-request behavior on a test PR touching one of these paths.

Out of Scope

• Assigning specific individuals if team ownership isn't yet finalized — use team/group handles or leave placeholders clearly marked for the team to fill in.

Acceptance Criteria

• CODEOWNERS entries added and verified to trigger auto-review-requests.

Files & Pointers

• CODEOWNERS
• BRANCH_PROTECTION.md

Dependencies / Related

None blocking.

Difficulty & Estimated Effort

Easy — ~half a day.