add base system

core/ai/ai_base/state.gd

@@ -0,0 +1,19 @@
+extends Node
+
+class_name State
+
+@export var state_id: String = ""
+
+signal transitioned(state, new_state_name)
+
+func enter()  -> void:
+	pass
+
+func exit()  -> void:
+	pass
+
+func update(_delta)  -> void:
+	pass
+
+func physics_update(_delta)  -> void:
+	pass