[CT-18] Build on-chain carrier certification registry contract

[mftee]

Problem

Carrier certifications (Operating License, Insurance, Safety, Hazmat) are verified by admins in a centralised off-chain process with no on-chain proof. Verified status can be disputed, altered, or lost in a database incident, with no immutable record of who verified what and when.

Proposed Solution

Create a CertificationRegistry contract inside contracts/package/certification-registry/ that provides an immutable, admin-controlled on-chain record of carrier certifications.

Note: All work must be done inside the contracts/package/ directory. Do not modify any existing contract files outside this folder.

Acceptance Criteria

• register_certification(carrier_wallet: Address, cert_type: Symbol, issuer_hash: BytesN<32>, expires_at: u64) — admin-only
• Supported cert types: OPERATING_LICENSE, INSURANCE, SAFETY, HAZMAT, VEHICLE_REG
• verify_certification(carrier_wallet, cert_type) returns { is_valid: bool, expires_at: u64, issuer_hash: BytesN<32> } — publicly callable
• revoke_certification(carrier_wallet, cert_type) — admin-only; marks cert as revoked
• Expired certifications (current time > expires_at) return is_valid: false from verify_certification without needing explicit revocation
• Unit tests cover: valid certification, expired certification, revoked certification, unknown certification

[phertyameen]

@phertyameen has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I’d like to work on this issue. I have experience with Soroban smart contracts, testing, and secure contract design, and I can implement the required functionality with clean, maintainable code and comprehensive test coverage.

I’ll follow the project requirements closely, keep changes scoped to the specified files/directories, and ensure the solution is reliable and CI-friendly.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @phertyameen to this issue.

[drips-wave]

Congratulations, @phertyameen! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @phertyameen: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

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