[Contracts] Add dispute resolution flow

[Kaylahray]

Description

The contract README explicitly calls out dispute resolution as a future enhancement, but the on-chain flow currently ends at donation, refund, or cancellation.

User Story

As a donor or requester,
I want to escalate a disputed help request or giveaway,
so that the contract can record a formal resolution path.

Requirements and Context

• Files: contracts/geev-core/src/mutual_aid.rs, contracts/geev-core/src/giveaway.rs, contracts/geev-core/src/test.rs
• Add a dispute state and a resolution function
• Restrict resolution to admin or authorized moderators
• Ensure a disputed request cannot continue normal payout flow until resolved

Suggested Implementation

// DISPUTE FLOW
// 1. Mark the request or giveaway as disputed.
// 2. Block normal completion or refund paths while disputed.
// 3. Add an admin resolution action.
// 4. Emit dispute lifecycle events.

Acceptance Criteria

• Disputed items can be marked on-chain.
• Normal completion or payout paths are blocked while disputed.
• Admin resolution changes the final state explicitly.

Submission Guidelines

• Branch: feat/dispute-resolution
• Depends on: request and giveaway state machine
• PR: feat(contracts): add dispute resolution lifecycle

[Mormentz]

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

i can and would love to work this issue.. please assign me this.

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

[bigvictoh]

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

I would love to work on this issue and contribute to the project.

I’ve reviewed the details and feel confident that I can investigate and implement a solid solution for this.

If this issue is currently unassigned and open for external contributors, could you please assign it to me? I will get started on a fix right away and submit a Pull Request as soon as it's ready.

Please let me know if there are any specific guidelines or approaches you'd like me to follow for this particular task.

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

[SweetBoy-eth]

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

Hello maintainer, I can handle this issue.

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

[drips-wave]

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

🧑‍💻 @SweetBoy-eth: 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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