[Contracts] Implement Fiat Payout Anchor Event Emitters

[ONEONUORA]

Description

Write event emission logic inside payout procedures:

• Detect if a beneficiary requires a fiat anchor off-ramp (metadata flag).
• Emit a Soroban event detailing the target bank routing info, amount, and recipient.
• The event will be picked up by the backend to execute Stellar Anchor SEP flows.

Acceptance Criteria

• Emits events with proper topics and structure.
• Includes exact amount and target address parameters.

[Promzy204-bad]

@Promzy204-bad has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue

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[drips-wave]

Congratulations, @Promzy204-bad! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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