fix: replace console.log with logger for unknown topic warning

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/nodeClass.js

@@ -41,7 +41,7 @@ class nodeClass {
           break;
         }
         default:
-          console.log("Unknown topic: " + msg.topic);
+          this.source.logger.warn(`Unknown topic: ${msg.topic}`);
       }
 
       if (done) {