[Contracts] Implement Multi-Signature Guardian Approval Thresholds

[ONEONUORA]

Description

Add multi-sig guardian validation:

• Owners can specify a list of guardian addresses and a threshold (e.g. 2 of 3).
• Payout triggers require guardians' co-signatures or approvals.

Acceptance Criteria

• Validates signatures against list.
• Rejects claims if threshold is not met.
• Event emission on guardian approvals.

[DavidAkere204]

@DavidAkere204 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

ℹ️ Repo Maintainers: To accept this application, review their application or assign @DavidAkere204 to this issue.

[drips-wave]

Congratulations, @DavidAkere204! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @DavidAkere204: 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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