[celo-contracts] Add a Paginated Vet Directory Query Function

[llinsss]

Background:
PetChainRegistry (celo-contracts/contracts/PetChainRegistry.sol) has no way to enumerate registered vets at all — vets is a mapping(address => Vet), so a caller must already know a vet's address to look them up; isVerifiedVet only answers yes/no for a known address.

Problem:
There is no on-chain or even reasonably-cheap-to-derive way to answer "show me all verified vets" without an off-chain indexer replaying every VetRegistered/VetVerified event from genesis.

What "done" looks like:

• An internal address[] private _vetAddresses is appended to on registration, and a paginated getVets(uint256 offset, uint256 limit) view function returns Vet structs for that page.
• Tests cover pagination and an empty registry.

Implementation guidelines:

• Key file: celo-contracts/contracts/PetChainRegistry.sol.

PR must include:

• New enumerable directory + paginated query
• Tests
• Passing Hardhat test run

[shadrach68]

@shadrach68 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue because I am a full-stack developer with 5+ years experience. I focus on identifying root causes and delivering clean, efficient, and maintainable solutions, with thorough testing to ensure reliable results.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @shadrach68 to this issue.

[CAESARIAN-ATHENS]

@Chidubemkingsley has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

PR submitted in few seconds. fast and attentive to details

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

[hman38705]

@hman38705 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hello dear maintainer i would love to work on this task along side you.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @hman38705 to this issue.

[drips-wave]

Congratulations, @hman38705! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @hman38705: 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

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[drips-wave]

This issue has been completed by @hman38705 as part of the Stellar Wave Program's 6th Wave 🥳

😎 @hman38705: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

🧑‍💻 Repo maintainers: How'd the contributor do? Leave a review to share your experience working with them.