Fix Godot 4.7 typed array crash: add freed-object filtering in PropertyPool and PerObjectHistory

addons/netfox/servers/data/per-object-history.gd

@@ -11,8 +11,14 @@ func _init(p_history_size: int):
 	_history_size = p_history_size
 
 func subjects() -> Array[Object]:
+	# Filter out freed objects — Godot 4.7 stricter typed arrays
+	# reject invalid references and crash the engine.
+	var valid := []
+	for o in _data.keys():
+		if is_instance_valid(o):
+			valid.append(o)
 	var result := [] as Array[Object]
-	result.assign(_data.keys())
+	result.assign(valid)
 	return result
 
 func is_auth(tick: int, subject: Object) -> bool:

addons/netfox/servers/data/property-pool.gd

@@ -49,8 +49,14 @@ func get_properties_of(subject: Object) -> Array[NodePath]:
 	return properties
 
 func get_subjects() -> Array[Object]:
+	# Filter out freed objects — Godot 4.7 stricter typed arrays
+	# reject invalid references and crash the engine.
+	var valid := []
+	for s in _properties_by_subject.keys():
+		if is_instance_valid(s):
+			valid.append(s)
 	var subjects := [] as Array[Object]
-	subjects.assign(_properties_by_subject.keys())
+	subjects.assign(valid)
 	return subjects
 
 func is_empty() -> bool: