Bubble up payer report verifier results

[fbac]

Return structured payerreport.VerifyReportResult from payerreport.Verifier.VerifyReport and update attestation worker logs to bubble up verifier reasons

Rename payerreport.Verifier.IsValidReport to payerreport.Verifier.VerifyReport and change its return type to payerreport.VerifyReportResult with IsValid and Reason. Update attestation worker to log utils.ReasonField and act on the structured result; add utils.ReasonField and switch mint success logs to utils.AmountField. Adjust tests and mocks to the new interface and result type. Note: fix a Go variable shadowing issue in VerifyReport where err is redeclared.

📍Where to Start

Start with the VerifyReport implementation in verifier.go, then review its callers in attestation.go and the updated tests in verifier_test.go.

Changes since #1264 opened

• Refactored variable declaration and removed unused code in PayerReportVerifier.VerifyReport method [9744de8]

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📊 Macroscope summarized 9744de8. 5 files reviewed, 2 issues evaluated, 2 issues filtered, 0 comments posted

🗂️ Filtered Issues

pkg/payerreport/verifier.go — 0 comments posted, 2 evaluated, 2 filtered

• line 136: VerifyReport treats reports with StartSequenceID == EndSequenceID as valid without verifying that PayersMerkleRoot equals the canonical hash of an empty set. The comment explicitly states the merkle root must always be the hash of an empty set, but the implementation returns IsValid: true unconditionally. This allows malformed empty reports with an incorrect PayersMerkleRoot to be accepted as valid, leading to incorrect attestations and downstream state inconsistency. [ Low confidence ]
• line 204: verifyMerkleRoot converts report.EndSequenceID from uint64 to int64 using a direct cast int64(report.EndSequenceID) when calling isAtMinuteEnd. If EndSequenceID exceeds math.MaxInt64, this conversion will wrap to a negative value, causing incorrect validation (e.g., mismatching the last sequence ID) and potentially rejecting valid reports. The rest of the codebase uses utils.Uint64ToInt64 to guard against overflow; the same check should be applied here to avoid silent overflow and logic errors. [ Low confidence ]

[graphite-app]

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