[CONTRACT-05] Add admin.require_auth() to all 5 contracts' initialize()

[mftee]

Overview

None of identity::initialize, shipment::initialize, escrow::initialize, document::initialize, or reputation::initialize call admin.require_auth() — they only guard against being called twice. Whoever calls initialize first becomes admin with no cryptographic proof they are who they claim, relying entirely on the deploy script calling it within the same transaction as deployment. This should be enforced by the contract itself, not just by deployment convention.

Technical Details

• Add admin.require_auth() as the first line of each of the 5 initialize() functions, immediately after the already-initialized check
• Add or update a test per contract confirming initialize fails when not signed by the claimed admin

Acceptance Criteria

• All 5 initialize() functions call admin.require_auth()
• Each contract has a test confirming initialize panics/fails when not signed by the claimed admin
• Existing passing tests continue to pass

[OluRemiFour]

I've reviewed the issue and understand the requirements. I'd love to work on this and submit a clean PR that meets the acceptance criteria.

[AbdulmujibOladayo]

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

I have reviewed this issue and its acceptance criteria carefully. The requirements are clear and well-scoped (large complexity). I have hands-on experience with testing and can implement this following the patterns and conventions already in the codebase. I will deliver complete, tested code that satisfies every acceptance criterion without requiring follow-up corrections. I can start immediately and am happy to discuss approach details with the maintainer beforehand.

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

[drips-wave]

Congratulations, @AbdulmujibOladayo! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

🧑‍💻 @AbdulmujibOladayo: 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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