Add settlement_status(id) as a cheaper read than the full Settlement record

[Jagadeeshftw]

📌 Description

settlement(env, id) returns the entire Settlement struct (id, anchor, asset, amount, fee, status, opened_at) even when a caller — such as an off-chain keeper deciding whether to call execute_settlement or cancel_expired_settlement — only needs the status field. is_settlement_expired already demonstrates the value of a narrow, purpose-built read over fetching and inspecting the full record.

🧩 Requirements and context

• Add settlement_status(env, id) -> Result<SettlementStatus, Error> returning Error::SettlementNotFound for a missing id, matching settlement's error behavior.
• Implement it via storage::get_settlement and project out just the status field (a full fetch is unavoidable given the current storage layout, but this still narrows the client-facing return type and payload).
• Document that this reduces cross-contract call payload size for keeper loops.

🛠️ Suggested execution

• Add the entrypoint to src/lib.rs, near settlement/settlement_exists.
• Add src/test.rs coverage for an existing settlement in each of the four SettlementStatus variants and for a missing id.
• Mention the new view in the README settlement table.

✅ Acceptance criteria

• settlement_status(id) returns the correct SettlementStatus for an existing settlement.
• It returns Error::SettlementNotFound for a nonexistent id, matching settlement's error.
• The full settlement(id) entrypoint is unchanged.

🔒 Security notes

A narrower read surface for keeper polling loops reduces the chance of a keeper accidentally branching on a stale or partially-read field from the larger struct, and keeps settlement-state checks auditable in one place.

📋 Guidelines

• Minimum 95% test coverage
• Clear documentation
• Timeframe: 96 hours

[Samaro1]

Gm gm boss. I would like to take this one on. I can add the settlement_status entrypoint returning just the SettlementStatus with matching SettlementNotFound error behavior, cover all four status variants plus the missing-id case in src/test.rs, and document the narrower read surface in the README settlement table. Please assign it to me.

[Jagadeeshftw]

Assigned @Samaro1 to this issue. Please open a PR referencing this issue (e.g. Closes #112) when you're ready. If you have questions along the way, feel free to join our contributor chat: https://t.me/+vTbe0hOUKrFhNTJl

[grantfox-oss]

🦊 GrantFox — @Samaro1 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #112)
2. Your PR will be reviewed by the AnchorNet-Org maintainers

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