## What changed
- Add the `apply_patch_preserve_line_endings` feature, disabled by default, to
preserve CRLF, CR, and mixed line endings when `apply_patch` updates files.
- Apply the feature consistently to built-in patch handling and patches invoked
through shell, user-shell, unified-exec, and app-server command execution.
- Keep the active feature configuration authoritative over inherited, shell
snapshot, and client-provided environment values.
## Testing
- Cover line-ending behavior with the feature enabled and disabled for custom
tool calls, shell heredocs, command execution, and the `apply_patch` CLI.
GitOrigin-RevId: 531a7c66761959c650270559f57941929f03e6c4