Review panel duplicates a changed file and misreports change totals

Summary

The Codex Review panel can show the same changed file multiple times and present an inconsistent change count for a single turn.

Observed behavior

During one turn that edited three files, the Review panel showed:

• Last Turn: +233 -273
• docs/bugs/003-ai-checkout-link-inline/fix-attempt-006.md: +34 -0
• docs/bugs/003-ai-checkout-link-inline/status.md: +5 -3
• EmSite/assets/js/checkout.js: +0 -270
• EmSite/assets/js/checkout.js: +192 -0
• EmSite/assets/js/checkout.js: +2 -0

The same checkout.js file appears three times. The review summary is therefore presented as separate file entries rather than one aggregated file-level change, and the displayed change totals are misleading when compared with the actual set of changed files.

Expected behavior

• Show each changed file once in the Review panel.
• Aggregate additions and deletions for that file.
• If separate edit operations or patches need to be shown, nest them under one file entry instead of duplicating the file.

Steps to reproduce

1. Start a Codex task in a Git repository.
2. Apply multiple edits or patches to the same file during one turn, along with edits to other files.
3. Open the Review panel and select the last-turn changes.
4. Observe that the repeatedly edited file appears as multiple file entries and that the change summary is not presented consistently as an aggregated file-level result.

Environment

• Codex Desktop app Version 26.908.70816
• Windows

Start at the Review panel's last-turn changes entry point and trace how repeated edits are converted into file entries and summary totals. Reproduce the three-edit case from the issue, then verify that each changed file appears once with aggregated additions and deletions, while any separate patches remain nested under that file.