Add Invoice Status State Machine

[mikewheeleer]

Implement Invoice Status State Machine

Description

Define and enforce valid invoice transitions such as draft, pending_verification, approved, funded, settled, and closed.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review

Suggested execution

• Fork the repo and create a branch
• git checkout -b feature/invoice-status-state-machine
• Implement changes
• Write backend code: status transition guard logic
• Write comprehensive tests: valid and invalid transition matrix
• Add documentation: README.md
• Include JSDoc-style comments
• Validate security assumptions

Test and commit

• Run tests
• Cover edge cases
• Include test output and security notes

Example commit message

feat(api): enforce deterministic invoice status transition rules

Guidelines

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

[Robotron2]

@Robotron2 has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Good day, I want to take this issue. I’ll implement a deterministic invoice state machine with enforced transition rules, add guard logic for valid/invalid transitions, cover the full transition matrix with tests, and include clear documentation, JSDoc comments, and security validation notes.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Robotron2 to this issue.

[drips-wave]

Congratulations, @Robotron2! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on March 30, 2026.

🧑‍💻 @Robotron2: 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 🌊