[Contract] Audit and harden `flash_loan_guard` against oracle freshness and sequencing attacks

[Solomonsolomonsolomon]

Extend the current price-snapshot model to handle stale or manipulated oracle data, delayed updates, and edge conditions around ledger timing. The goal is to make the guard defensible under adversarial market conditions, not just basic happy-path checks.

[king-aj-the-first]

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

Hii, i'd like to work on this issue

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[devmasalati]

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

hi maintainer, i'm a full stack developer with years of experience. i would love to work on this issue. kindly assign

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[tecch-wiz]

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

I’m interested in tackling this! I have a strong background in smart contract development and full-stack systems, so I'm well-equipped to handle the requirements here. Could you please assign this to me?

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[Caneryy]

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

Hi, I'd like to work on this issue please.

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

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