Add jointly-administered offering via existing multisig handoff into register_offering

[thlpkee20-wq]

Description

Co-administration today requires a wrapper multisig contract. Provide a first-class register_offering_multisig entry that takes a multisig contract address and stores it as the canonical issuer principal, with documented expectations on require_auth resolution against the multisig.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: Revora-Contracts/src/lib.rs, Revora-Contracts/src/test_multisig_gas.rs
• Multisig contract must be assert-callable before registration completes

Suggested execution

• Fork the repo and create a branch
• git checkout -b feat/multisig-administered-offerings
• Implement changes
  • Add register_offering_multisig(multisig: Address, ...)
  • Sanity-call multisig get_threshold() via cross-contract invoke to fail-fast
  • Document indexer mapping is_multisig_admin=true field on off_reg event
• Validate security and correctness assumptions

Test and commit

• Run tests
  • cargo test --all
• Cover edge cases
  • Multisig contract that does not implement get_threshold must fail registration cleanly
• Include test output and security notes

Example commit message

feat: add register_offering_multisig for jointly-administered offerings

Guidelines

• Minimum 95 percent test coverage
• Clear documentation
• Timeframe: 96 hours

[Achievers-sketch]

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

Experienced with Soroban smart contracts and multisig integrations. I’ll implement secure multisig-administered offerings, fail-fast validation, tests, and documentation.

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

[drips-wave]

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

🧑‍💻 @Achievers-sketch: 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 — @Achievers-sketch has been assigned to this issue!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #453)
2. Your PR will be reviewed by the RevoraOrg maintainers

Good luck! Track your progress on GrantFox.