Gemini also not compatible with the tmpdir approach for large diffs

[wesm]

see for example

Error executing tool grep_search: Path not in workspace: Attempted path
"/var/folders/y4/03b2815n4654w99z_fpwm1k40000gn/T/roborev-snapshot-433371329/roborev-snapshot-content.diff" resolves
outside the allowed workspace directories: /Users/wesm/code/kata or the project temp directory:
/Users/wesm/.gemini/tmp/kata

[mariusvniekerk]

@wesm should we write these to a $repo_root/tmp instead ?