Show type-changed files in commit diffs

[Eagl61]

Objective

Zed ignores files marked by Git as type-changed (T), causing commits containing only these changes to show 0 Changed Files.

For example, commit d7cc949 changes crates/eval_utils/LICENSE-GPL from a regular file to a symlink, but Zed displays no changes.

Solution

Handle TypeChanged files like modified files by loading both their old and new contents.

Testing

• Added parser coverage for the T status.
• Added a repository test for a regular-file-to-symlink change.
• Ran cargo test -p git.
• Ran ./script/clippy -p git.
• Manually verified the example commit on macOS.

Self-Review Checklist:

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content adheres to Zed's UI standards (UX/UI and [icon](https://github.com/zed-
  industries/zed/blob/main/crates/icons/README.md) guidelines)
• Tests cover the new/changed behavior
• Performance impact has been considered and is acceptable

Showcase

Before:

After:

———

Release Notes:

• Fixed type-changed files not appearing in Git Graph and commit views.

[cla-bot]

Thank you for your pull request and welcome to our community. We could not parse the GitHub identity of the following contributors: Eagl61.
This is most likely caused by a git client misconfiguration; please make sure to:

1. check if your git client is configured with an email to sign commits git config --list | grep email
2. If not, set it up using git config --global user.email email@example.com
3. Make sure that the git commit email is configured in your GitHub account settings, see https://github.com/settings/emails

[cla-bot]

We require contributors to sign our Contributor License Agreement, and we don't have @Eagl61 on file. You can sign our CLA at https://zed.dev/cla. Once you've signed, post a comment here that says '@cla-bot check'.

[Eagl61]

@cla-bot check

[cla-bot]

We require contributors to sign our Contributor License Agreement, and we don't have @Eagl61 on file. You can sign our CLA at https://zed.dev/cla. Once you've signed, post a comment here that says '@cla-bot check'.

[cla-bot]

The cla-bot has been summoned, and re-checked this pull request!

[Eagl61]

@cla-bot check

[cla-bot]

The cla-bot has been summoned, and re-checked this pull request!

[zed-industries-bot]

	Warnings
⚠️	This PR is missing release notes. Please add a "Release Notes" section that describes the change: Release Notes: - Added/Fixed/Improved ... If your change is not user-facing, you can use "N/A" for the entry: Release Notes: - N/A

Generated by 🚫 dangerJS against ed3a445

[ChristopherBiscardi]

thanks!