chore(deps): update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/coana-guardrail.yml

@@ -22,7 +22,7 @@ jobs:
           echo "all_changed_files=$(git diff --name-only ${{ github.base_ref }} ${{ github.head_ref }} | tr '\n' ' ')" >> $GITHUB_OUTPUT
 
       - name: Use Node.js 24.x
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 24.x