[BUG] Add a setting to disable the changes-view git diff on large repos

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

On Windows desktop app v1.15962, the app repeatedly runs git diff --no-textconv --numstat -M HEAD (and against the session's base commit) to populate the changes/diff view. On a large, high-churn monorepo this is catastrophic: my repo has ~588,000 tracked files with ~35,700 changed in the working tree, so each --numstat reads tens of thousands of large blobs and the git processes balloon to 8-12 GB RAM while saturating the disk at ~170 MB/s. It re-triggers on file churn.

I never use the changes view. I'd like a way to turn off the automatic diff computation that backs it — e.g. a settings.json key or environment variable. Today there's no documented toggle; fileCheckpointingEnabled and includeGitInstructions don't affect these invocations.

Bonus: respecting a local core.fsmonitor/cheap-diff path, or honoring .git/info/attributes more aggressively, would also help — but a simple "don't compute the changes-view diff" switch is what I'm after.

What Should Happen?

Claude should not repeatedly peg my disk at 100%

Error Messages/Logs

Steps to Reproduce

See above.

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

1.15962.0 (039543)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_