Implement production vertical slice foundation

game/domain/dive/dive_alert_level.gd

@@ -0,0 +1,18 @@
+class_name DiveAlertLevel
+extends RefCounted
+
+enum Value {
+	NORMAL,
+	ATTENTION,
+	RETURN,
+	CRITICAL,
+	FAILURE,
+}
+
+
+static func highest(levels: Array[Value]) -> Value:
+	var result := Value.NORMAL
+	for level: Value in levels:
+		if level > result:
+			result = level
+	return result