Use the cube of similarity

This has the effect of cranking up the similarity threshold dramatically

projects/tentacles/src/tentacles/workers.py

@@ -84,11 +84,11 @@ def poll_printers(app: App, db: Db) -> None:
                 "/api/plugin/bedready",
                 json={
                     "command": "check_bed",
-                    "similarity": 0.94,
                     "reference": snapshots[0],
                 },
             )
-            return status.get("bed_clear", True)
+            similarity = status["similarity"] ** 3 # Cube it
+            return similarity > 0.9
 
         printer_job = {}
         try: