Backend: Add GDPR data export and deletion endpoints

[CelestinaBeing]

Summary

Trivela collects wallet addresses and campaign activity data. While wallet addresses are pseudonymous, GDPR and similar privacy regulations require platforms to provide data export and deletion upon user request — especially relevant as Trivela targets EU users in the Stellar ecosystem.

Problem

• No data export endpoint for users to download their data
• No deletion endpoint to remove user-associated records
• Audit logs reference wallet addresses which may constitute personal data in some jurisdictions

Acceptance Criteria

• Add GET /api/v1/user/:walletAddress/export — returns all data associated with a wallet address:
  • Campaign audit log entries where the wallet was the actor
  • Any campaign records created by this wallet (if wallet auth from issue Backend: Add wallet-signature-based auth for campaign creation/management #302 is implemented)
  • Returns as JSON with a application/json download header
• Add DELETE /api/v1/user/:walletAddress — pseudonymizes wallet address in all records (replace with [REDACTED:sha256_prefix])
• Both endpoints require wallet signature auth (issue Backend: Add wallet-signature-based auth for campaign creation/management #302) to prevent abuse
• Add rate limiting: max 3 export/delete requests per day per wallet
• Log all data export and deletion requests in audit log (with redacted wallet)
• Add unit tests for export completeness and deletion pseudonymization
• Add GDPR section to docs/DEPLOYMENT.md

References

• backend/src/dal/auditLogRepository.js
• backend/src/middleware/apiKeyAuth.js

[presidojay1]

@presidojay1 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I would like to work to on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @presidojay1 to this issue.

[drips-wave]

Congratulations, @presidojay1! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @presidojay1: 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 🌊

[drips-wave]

This issue has been completed by @presidojay1 as part of the Stellar Wave Program's 5th Wave 🥳

😎 @presidojay1: 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.

🧑‍💻 Repo maintainers: How'd the contributor do? Leave a review to share your experience working with them.