[.github] Fix claude-review fork fetch — point origin to fork repo

claude-code-action@v1 unconditionally runs `git fetch origin <branch>`
even when the branch is already checked out locally. For fork PRs, the
branch doesn't exist on the base repo's origin.

Fix: after checking out the PR code, repoint origin to the fork's repo
URL so the action's internal fetch finds the branch. For same-repo PRs
this is a no-op. Existing refs (origin/main etc.) are preserved from
the initial checkout.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: matthallett1

.github/workflows/claude-review.yml

@@ -49,6 +49,13 @@ jobs:
           BRANCH=$(gh pr view "${PR_NUMBER}" --json headRefName -q .headRefName)
           git checkout -B "${BRANCH}" refs/remotes/origin/pr-head
 
+          # Point origin to the fork repo so claude-code-action can fetch the branch.
+          # For same-repo PRs this is a no-op (URL stays the same).
+          FORK_URL=$(gh pr view "${PR_NUMBER}" --json headRepository -q '.headRepository.url')
+          if [ -n "$FORK_URL" ]; then
+            git remote set-url origin "${FORK_URL}"
+          fi
+
       - uses: anthropics/claude-code-action@v1
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}