refactor to state machine

scripts/states/idle.gd

@@ -1,4 +1,19 @@
 extends State
 
 func process_physics(delta: float) -> State:
-	return
+	if not multiplayer.is_server():
+		return
+
+	var target_velocity = Vector3(0, subject.velocity.y, 0)
+	subject.velocity = subject.velocity.move_toward(target_velocity, subject.acceleration * delta)
+	subject.velocity += Main.gravity_velocity
+	subject.move_and_slide()
+
+	if not subject.is_on_floor():
+		return %Fall
+
+	var input_direction = %Input.direction
+	if input_direction.length() < 0.05:
+		return
+
+	return %Run