added enemy state machine with idle, stunned, and dead states

scripts/StateMachine.gd

@@ -0,0 +1,39 @@
+extends Node
+
+@export var initial_state : State
+
+var current_state : State
+var states : Dictionary = {}
+
+func _ready() -> void:
+	for child in get_children():
+		if child is State:
+			states[child.name.to_lower()] = child
+			child.Transitioned.connect(on_child_transition)
+	
+	if initial_state:
+		initial_state.Enter()
+		current_state = initial_state
+
+func _process(delta: float) -> void:
+	if current_state:
+		current_state.Update(delta)
+
+func _physics_process(delta: float) -> void:
+	if current_state:
+		current_state.Physics_Update(delta)
+
+func on_child_transition(state,new_state_name):
+	if state != current_state:
+		return
+		
+	var new_state = states.get(new_state_name.to_lower())
+	if !new_state:
+		return
+	
+	if current_state:
+		current_state.Exit()
+		
+	new_state.Enter()
+	
+	current_state = new_state