[Contracts] Implement close_plan / Refund Functionality

[ONEONUORA]

Description

Allow plan owners to cancel their inheritance plans early:

• Authenticate that the caller is the plan owner.
• Transfer all locked tokens and accrued interest back to the owner.
• Delete the plan from persistent contract storage.

Acceptance Criteria

• Rejects non-owners.
• Returns full token balance.
• Safely cleans up the storage slot to refund gas/rent.

[ekwe7]

I would love to work on this issue. I have experience building production ready applications and collaborating through GitHub workflows. I'll carefully analyze the current implementation, propose a reliable solution, and submit a well-tested PR. My focus is on clean code, maintainability, and timely delivery

[Dopezapha]

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

Hey maintainer, I would love to work on this issue. I have years of experience as a software engineer and smart contract developer, and I'm confident I can implement everything required here. Kindly assign it to me so I can begin working immediately

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

[Windowlight]

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

I’m interested in this issue and believe my experience with contracts, backend systems, and frontend implementation makes me a good fit. Happy to provide updates as I work through it.

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

[Luluameh]

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

Hello,

I’ve resolved similar problems in the past and am confident I can implement a clean, efficient fix quickly if I am given the opportunity.

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

[drips-wave]

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

🧑‍💻 @Luluameh: 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 🌊

[grantfox-oss]

🦊 GrantFox — @Luluameh has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #836)
2. Your PR will be reviewed by the Fracverse maintainers

Good luck! Track your progress on GrantFox.