[SCF high][easy] Reject stale coordinator state transitions

[karagozemin]

Goal\nPrevent delayed resolver events from moving an order back to an earlier lifecycle state.\n\n## Acceptance criteria\n- Define monotonic order-state transitions.\n- Ignore or reject stale events deterministically.\n- Add out-of-order event tests.\n\n## Complexity\nHigh - small implementation, high reliability value.

[Marvelg256]

@Marvelg256 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi Maintainer! I'd like to work on this issue. I'm confident I can complete this task and submit a PR within 24 hours.

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[iyiade08]

@iyiade08 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello, having gone through the acceptance criteria, I'm confident this is a task I can complete to a high standard. I'd be glad to be assigned and get started.

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[VeronicDev]

@VeronicDev has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi! I can fix this pls assign

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[Fury03]

@Fury03 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I can work on this

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[oscarj007]

@oscarj007 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hii
I'd love to take up this issue and resolve it please🙏

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[emrekayat]

@emrekayat has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

let me work on it

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[drips-wave]

Congratulations, @emrekayat! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @emrekayat: 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.

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