Performance degradation in Codex App with large Git changes, even when Diff Editor is not open

What version of the Codex App are you using (From “About Codex” dialog)?

260206.1448 (565)

What subscription do you have?

Plus

What issue are you seeing?

Codex App becomes noticeably slow when the Git working tree contains very large changed data files, even if I never open the diff view.
I can reproduce this in two ways:

1. One very large JSON file (300,000 records)
2. Many JSON files in one folder (up to 1,000 records per file)

In both cases, performance drops while just navigating/using the app normally.

What steps can reproduce the bug?

Reproduction A: Single Large File

1. Open repo
2. Generate one large JSON file:

``bash
./generate-large-json.sh large-test.json 300000
``

1. Open Codex App on this repo.
2. Do not open the diff editor for large-test.json.
3. Use the app normally (chat, file navigation, etc.).

Reproduction B: Many Medium Files

1. Open repo
2. Generate many JSON files in a dedicated folder:

``bash
./generate-many-json-files.sh stress-folder 500 1000
``

1. Open Codex App on this repo.
2. Do not open diff editor for those files.
3. Use the app normally.

generate-large-json.sh
generate-many-json-files.sh

What is the expected behavior?

Codex App should remain responsive when large/ many changed files exist in Git, unless the diff view for those files is explicitly opened.

Additional information

Codex App becomes slow/laggy even without opening any diff for the large changed files.