Pass GITHUB_TOKEN to macOS CI step to fix 403 rate-limit errors

Unauthenticated GitHub API calls share the runner IP (60 req/hour limit).
net.go already uses GITHUB_TOKEN as a Bearer token when present.
gh CLI also needs GH_TOKEN to authenticate for gh extension install.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/workflows/integration.yml

@@ -53,6 +53,9 @@ jobs:
           mkdir -p ~/.pyenv
 
       - name: Run bootstrap tool
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
           echo y | ./bootstrap_environment --only custom --no-vm --no-ai