[StuartFerguson]

Summary

• Reduce GetDetailsForTransaction cyclomatic complexity below the Codacy threshold.
• Extract merchant, contract, product, and device validation/lookup helpers.
• Preserve existing behavior and error messages.

Verification

• dotnet test FileProcessor.BusinessLogic.Tests/FileProcessor.BusinessLogic.Tests.csproj --no-restore (100 passed)
• Other unit and aggregate test projects passed in the solution run.
• Integration tests hung without output and were stopped after a bounded wait.

Fixes #792

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-10T12:38:45.419509Z	efab930	PR opened

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[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Metrics 9 complexity · 0 duplication

Metric	Results
Complexity	9
Duplication	0

View in Codacy

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