Add modular CSS checks

modules/css.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+set -euo pipefail
+
+echo "========================"
+echo " Davidson CI - CSS"
+echo "========================"
+
+CSS_COUNT="${DAVIDSON_CSS_COUNT:-0}"
+
+if [ "$CSS_COUNT" -eq 0 ]; then
+    echo "No CSS files detected - skipping CSS module"
+    exit 0
+fi
+
+echo
+echo "CSS files detected: $CSS_COUNT"
+echo
+
+echo "→ CSS lint"
+
+if [ -f package.json ] && \
+   node -e "let p=require('./package.json'); process.exit(p.scripts?.['lint:css'] ? 0 : 1)"
+then
+    npm run lint:css
+else
+    echo "No lint:css script configured - skipping"
+fi
+
+echo
+echo "CSS module completed successfully"