Add NFT transfer authorization tests for commitment_nft::transfer of active commitments

[1nonlypiece]

📌 Description

commitment_nft::transfer (line ~915) moves a commitment NFT, but the interaction
between transfers and the underlying active commitment in commitment_core is
security-sensitive: transferring an NFT effectively transfers a liquidity obligation.
docs/commitment_nft/SETTLEMENT_AUTHORIZATION.md describes the authorization model,
yet transfer-of-active-commitment authorization is not fully tested.

This issue adds authorization and ownership-consistency tests for transfers.

🎯 Requirements and Context

• Assert only the current owner (require_auth) can transfer; non-owner transfer rejected.
• Assert balance_of, owner_of, and get_nfts_by_owner stay consistent after transfer.
• Assert transfer of an inactive/settled token behaves per the documented policy.
• Assert is_authorized contracts can/cannot transfer per the access-control model.

🛠️ Suggested Execution

1. Fork the repo and create a branch

git checkout -b test/nft-transfer-auth

2. Implement changes

• Add tests to contracts/commitment_nft/src/tests.rs.
• Cross-reference docs/commitment_nft/SETTLEMENT_AUTHORIZATION.md.

3. Test and commit

• Run: cargo test --target wasm32v1-none --release
• Edge cases: owner transfer, non-owner rejected, settled-token transfer, balance/owner consistency.

Example commit message

test: transfer-authorization coverage for commitment_nft

✅ Guidelines

• Minimum 95% test coverage on the transfer path.
• Document the authorization scenarios.
• Timeframe: 96 hours.

🏷️ Labels

type-testing · type-security · area-contracts · MAYBE REWARDED · GRANTFOX OSS · OFFICIAL CAMPAIGN

💬 Community & Support

• Join the CommitLabs contributor Discord to coordinate and get unblocked fast: https://discord.gg/WV7tdYkJk
• Introduce yourself before starting to avoid duplicate work.
• Maintainers triage actively and review fast.

[dangelo352]

I'd like to take this one. I'll keep the PR focused on commitment_nft transfer authorization coverage: current-owner transfer, non-owner rejection, balance/owner/index consistency after transfer, and documented active/inactive transfer behavior.