Implement Stellar transaction verification service

[ayshadogo]

User Story:
As a developer, I want a service that verifies Stellar transactions so that only valid on-chain donations are recorded.
Acceptance Criteria:

• Fetches transaction from Stellar Horizon by txHash
• Verifies: destination matches campaign contract, operation type = payment, asset matches accepted assets
• Throws if transaction not found or not yet confirmed
• Retries up to 3 times with exponential backoff

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[Deyanju23]

@Deyanju23 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I can resolve this issue, please assign.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Deyanju23 to this issue.

[Power70]

@Power70 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi maintainer,

I can work on this issue

Kindly assigned it to me

Thank you

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Power70 to this issue.

[Ssoleed]

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

Good day, please I am committed to my work on drips and I assure you the job completion on time .I would love to work on this issue maintainer. Please Assign me and I'll get the job done.

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

[Cedarich]

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

Hello maintainer can i take up this task

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

[drips-wave]

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

🧑‍💻 @Cedarich: 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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[drips-wave]

This issue has been completed by @Cedarich as part of the Stellar Wave Program's 5th Wave 🥳

😎 @Cedarich: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

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