chore: add check for uncommitted changes post-deploy

Author: Jay Prall

.github/workflows/deploy.yml

@@ -82,3 +82,24 @@ jobs:
 
     - name: Invalidate Cloudfront
       run: aws cloudfront create-invalidation --distribution-id ${{ steps.terragrunt_output.outputs.distribution_id }} --paths "/*"
+
+    - name: Check for uncommitted changes
+      run: |
+        git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+        echo "Git status after build:"
+        git status
+
+        CHANGES="$(git status --porcelain)"
+        if [ -n "$CHANGES" ]; then
+          echo "❌ Uncommitted changes detected in the repository."
+          echo "These files changed (format: XY path):"
+          echo "$CHANGES"
+
+          echo "::error::Your deployment produced uncommitted changes. \
+          This usually means something should be added to .gitignore or a lockfile/other tracked file needs updating."
+          exit 1
+        else
+          echo "✅ No uncommitted changes after deploy."
+        fi
+