Add regression test for protocol treasury balance unchanged after failed trade

[Chucks1093]

Summary
When a trade fails, no fees should be transferred to the protocol treasury. A regression test that records the treasury balance before a failed trade and asserts it is unchanged afterward confirms no partial fee transfer occurs on failure.

Scope

• add a regression test that records the protocol treasury balance before a trade that is expected to fail
• trigger the failing trade
• assert the treasury balance is identical after the failed call

Acceptance Criteria

• the treasury balance is unchanged after a failed trade
• the test covers at least one buy failure and one sell failure
• the assertion uses the read-only treasury address and balance check

Contributor coordination: if you pick this up, reach out in Telegram for updates or clarification: https://t.me/accesslayerorg

[Kingvic300]

@Kingvic300 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I would love to work on this

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Kingvic300 to this issue.

[Nuel-ship-it]

@Nuel-ship-it has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi maintainer, please can you assign me this? Thank you

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[shadrach68]

@shadrach68 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

hi, please assign this issue to me.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @shadrach68 to this issue.

[drips-wave]

Congratulations, @Kingvic300! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @Kingvic300: 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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