- Add git_local.py: fetch, checkout PR branch, generate git diff against
target, restore branch after review
- Update fetch_pr_details to use local git diff when REPOS_BASE_DIR is set,
with fallback to AzDo iteration API
- Update run_code_review to restore repo to target branch after review
- Refine Claude review prompt to only comment on diff changes, not
pre-existing code
- Update README: WSL venv gotcha, local git checkout flow, flow diagram
