[CT-20] Write comprehensive tests for asset-maintenance contract in opsce crate

[yusuftomilola]

Problem

contracts/asset-maintenance/src/test.rs exists but has near-zero coverage. Maintenance record creation, alert generation, and warranty checking are completely untested.

Proposed Solution

Create contracts/opsce/src/maintenance_tests.rs with a full test suite using the Soroban test environment. Mock ledger timestamps to test time-dependent logic.

Acceptance Criteria

• create_maintenance_record() — success path, invalid asset ID fails
• get_maintenance_records() — returns correct records after multiple creates
• check_maintenance_alerts() — no alerts when none due, correct severity at each time threshold (7, 3, 1 day, overdue)
• register_warranty() — success path, status is Active before expiry
• check_warranty_status() — returns Expired after mocking ledger timestamp past expiry
• rate_provider() — correct average after multiple ratings, duplicate rating rejected
• Tests run cleanly with cargo test -p asset-maintenance

[nafiuishaaq]

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

Let me professionally implement this task as soon as possible with an ETA of 2 to 4 hours

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

[drips-wave]

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

🧑‍💻 @nafiuishaaq: 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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