Implement cross-key arbitrage protection with price impact circuit breaker

[Chucks1093]

Summary

Add a circuit breaker to the bonding curve contract that pauses trading when a single transaction's price impact exceeds a configurable threshold, preventing large manipulative trades.

Scope

• max_price_impact_bps configured per key by creator
• Impact computed as percentage price change from pre- to post-trade price
• Trade rejected with CircuitBreakerTripped error when impact exceeds threshold
• set_circuit_breaker(key_id, max_bps) — creator-only config
• CircuitBreakerTripped event emitted with actual impact bps

Acceptance Criteria

• Trade blocked when single-transaction impact exceeds max_bps
• Trade succeeds when impact is within threshold
• set_circuit_breaker restricted to creator wallet
• CircuitBreakerTripped event includes correct actual_bps
• Threshold of 0 disables circuit breaker (default)

ETA

24 hours

[LayanGift]

@LayanGift has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

I can handle this issue and will like to work on it, Please assign thank you.

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[ejiromowarin]

@ejiromowarin has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

hey maintainer, please kindly assign this to me, i can surely fix it

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[mysterio123865]

@mysterio123865 has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

Hello I will like resolve this
will implement everything as stated and submit a well tested result without cl failure

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[oscarj007]

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Can I work on this issue please

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[Jessicaayegh]

@Jessicaayegh has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

Please assign

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[victrexfx]

@victrexfx has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

Kindly assign to me please

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[VictorEzenma]

@VictorEzenma has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

I can solve this issue

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[drips-wave]

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

🧑‍💻 @VictorEzenma: 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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