Add createSep31DirectPayment function

[MissBlue00]

Task

Add a createSep31DirectPayment function to implement SEP-31 direct payments.

Details

• Function signature: createSep31DirectPayment(params: DirectPaymentParams): Promise<DirectPaymentResult>
• Implement Stellar SEP-31 direct payment flow
• Handle sender and receiver KYC via SEP-12
• Include original transaction reference
• Add DirectPaymentParams and DirectPaymentResult interfaces
• Integration point: anchor-service package

Test

Run pnpm --filter @stellar-pay/anchor-service build to verify no TypeScript errors.

[gracekenn]

@gracekenn has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Hi. Please let me work on this issue

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

[drips-wave]

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

🧑‍💻 @gracekenn: 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.

Warning

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