Cover GDPR data-deletion paths in compliance tests

[nanaf6203-bit]

Problem Statement

contracts/gdpr/lib.rs.tests for withdraw_consent exist but no clean-up of derived data (timelines, audit hashes).

Why it matters

GDPR Article 17 — right to erasure — requires that all derived identity traces become unreachable.

Technical Context

Add tests asserting: after withdraw_consent, (subject, purpose) returns false; cross-references in audit log are tombstoned; storage is reclaimable.

Expected Outcome

Withdraw consent purges all derived references.

Acceptance Criteria

1. cargo test -p propchain-gdpr includes 5 new withdrawal cases.
2. Tombstone coverage documented.
3. New tests/gdpr_erasure.rs.
4. SDK updated.

Implementation Notes

Add explicit withdraw_consent test vectors.

Files or modules likely to be affected

contracts/gdpr/lib.rs, tests/.

Dependencies

None.

Difficulty level

MEDIUM.

Estimated effort

M (~2 days).

[godwinishaku506-hub]

@godwinishaku506-hub has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi Maintainer, i would love to work on this issue

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[ykargeee-bit]

@ykargeee-bit has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi Maintainer,

I’m a full-stack developer, and I’d like to contribute to the task. I’ll implement it carefully and efficiently thoroughly understand requirements and edge cases
Communicate promptly about suggestions or improvements. And I will provide regular progress updates and address blockers
Align with project goals through feedback and clarification.

Thank you,

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

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