fix(contracts): move consumedIntents assignment before external call (CEI)

[iap]

Summary

Fixes a CEI (Checks-Effects-Interactions) pattern violation in MARKSettlementModule._consumeAndValidate.

Root cause

consumedIntents[intentId] = true was set after the external call to verifier_.verifySettlement(). The current verifier is view so reentrancy is not possible today, but this would become a real reentrancy vector if a future non-view verifier is plugged in.

Fix

Move consumedIntents[intentId] = true to before the external call. No behaviour change for the current verifier.

Verification

All tests pass.

Scope

• contracts/src/settlement/MARKSettlementModule.sol
• contracts/THREAT_MODEL.md

Risk

Low — no behaviour change for current verifier. Improves correctness for future verifier integrations.

Summary by CodeRabbit

• Bug Fixes

  • Adjusted intent consumption validation order in settlement operations to enhance protection against potential intent reuse.

• Documentation

  • Updated protocol invariants documentation regarding intent consumption validation and verification ordering to align with implementation.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 63b1f33b-f41a-43a1-b905-cb8aa1ba8da9

📥 Commits

Reviewing files that changed from the base of the PR and between 3b5720b and c39890b.

📒 Files selected for processing (2)

• contracts/THREAT_MODEL.md
• contracts/src/settlement/MARKSettlementModule.sol

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Walkthrough

This PR reorders the intent consumption check in _consumeAndValidate to set consumedIntents[intentId] = true before the optional external verifier call, implementing the CEI (Checks-Effects-Interactions) pattern for replay and reentrancy protection. The threat model documentation is updated to reflect this ordering.

Changes

Intent Consumption Replay Protection

Layer / File(s)	Summary
Core Implementation contracts/src/settlement/MARKSettlementModule.sol	In _consumeAndValidate, consumedIntents[intentId] = true is moved to execute before the optional external verifier_.verifySettlement() call, ensuring intent consumption is recorded in state (Effects phase) before external interactions occur.
Threat Model Documentation contracts/THREAT_MODEL.md	Invariant #2 updated to document the revised ordering: consumedIntents[intentId] is set to true before the external verifier call, with explicit reference to CEI pattern for replay/reentrancy protection in case future verifier implementations become non-view.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• trade/mark#68: Adds the initial THREAT_MODEL.md; this PR updates that document alongside the corresponding code change.
• trade/mark#69: Both PRs modify the same invariant and _consumeAndValidate consumption/validation ordering but make opposing changes to the timing of consumedIntents assignment.
• trade/mark#26: Adds tests for settlement verification and consumption behavior; related to the verification/consumption changes in this PR.

Poem

🐰 Intent once consumed, cannot be twice,
CEI patterns keep the protocol nice,
Mark state before calling out,
Replay's what we're guarding about! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically summarizes the main change: moving consumedIntents assignment before an external call to follow CEI pattern.
Description check	✅ Passed	The description covers summary, root cause, fix, verification, scope, and risk assessment, addressing most template sections comprehensively.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/cei-consumed-intents

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