fix: rename all bare shell vars to _prefix - Cloud Build compatibility

cloudbuild.yaml

@@ -66,10 +66,10 @@ steps:
           --secret=webhook-url \
           --project=${PROJECT_ID} 2>/dev/null || echo "")
         if [[ -n "$_WH_URL" ]]; then
-          MSG="✅ *OSVauco Deploy fullført*\nCommit: \`$COMMIT_SHA\`\nService: \`${_CLOUD_RUN_SERVICE}\`\nRegion: \`${_REGION}\`"
+          _NOTIFY_MSG="✅ *OSVauco Deploy fullført*\nCommit: \`$COMMIT_SHA\`\nService: \`${_CLOUD_RUN_SERVICE}\`\nRegion: \`${_REGION}\`"
           curl -s -X POST "$_WH_URL" \
             -H 'Content-Type: application/json' \
-            -d "{\"text\": \"$MSG\"}" || true
+            -d "{\"text\": \"$_NOTIFY_MSG\"}" || true
           echo "✓ Deploy-notifikasjon sendt"
         else
           echo "⚠️ Ingen webhook-url i Secret Manager — hopper over varsling"