Fix multiline commit message that was breaking YAML parsing

Author: jamiew

.github/workflows/generate-site.yml

@@ -33,8 +33,6 @@ jobs:
           if git diff --staged --quiet; then
             echo "No changes to commit"
           else
-            git commit -m "Regenerate GitHub Pages site
-
-Generated by Claude API from docs/site-prompt.md"
+            git commit -m "Regenerate GitHub Pages site" -m "Generated by Claude API from docs/site-prompt.md"
             git push
           fi