docs: Add threshold/logging screenshot to README

Author: rcourtman

README.md

@@ -25,6 +25,9 @@ A lightweight monitoring application for Proxmox VE that displays real-time stat
 **Backups Tab:**
 ![Backups View](docs/images/05-backups-view.png)
 
+**Threshold Logging:**
+![Threshold Logging View](docs/images/06-thresholds-logging.png)
+
 </details>
 
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