fix: rename WEBHOOK_URL to WH_URL to avoid Cloud Build substitution parse error

cloudbuild.yaml

@@ -62,12 +62,12 @@ steps:
     args:
       - '-c'
       - |
-        WEBHOOK_URL=$(gcloud secrets versions access latest \
+        WH_URL=$(gcloud secrets versions access latest \
           --secret=webhook-url \
           --project=${PROJECT_ID} 2>/dev/null || echo "")
-        if [[ -n "$WEBHOOK_URL" ]]; then
+        if [[ -n "$WH_URL" ]]; then
           MSG="✅ *OSVauco Deploy fullført*\nCommit: \`$COMMIT_SHA\`\nService: \`${_CLOUD_RUN_SERVICE}\`\nRegion: \`${_REGION}\`"
-          curl -s -X POST "$WEBHOOK_URL" \
+          curl -s -X POST "$WH_URL" \
             -H 'Content-Type: application/json' \
             -d "{\"text\": \"$MSG\"}" || true
           echo "✓ Deploy-notifikasjon sendt"