Backend: Add UUID validation to endpoints

[ONEONUORA]

Problem

Some endpoints accept UUID strings without validation.

Impact

• Invalid UUID acceptance
• Potential crashes
• Data integrity issues

Solution

Add UUID validation to all endpoints accepting UUID parameters.

Files to Modify

• All API endpoint modules

Priority

Medium - Input validation

[Joseph-1-Duro]

@Joseph-1-Duro has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi I would love to work on your project

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Joseph-1-Duro to this issue.

[drips-wave]

Congratulations, @Joseph-1-Duro! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @Joseph-1-Duro: 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

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊