card: fix cruise speed initialization w/ buttons (#34386)

* fix initialize w/ buttons

* what

* comment

selfdrive/car/card.py

@@ -72,6 +72,7 @@ def __init__(self, CI=None, RI=None) -> None:
     self.can_rcv_cum_timeout_counter = 0
 
     self.CC_prev = car.CarControl.new_message()
+    self.CS_prev = car.CarState.new_message()
     self.initialized_prev = False
 
     self.last_actuators_output = structs.CarControl.Actuators()
@@ -182,7 +183,8 @@ def state_update(self) -> tuple[car.CarState, structs.RadarDataT | None]:
 
     self.v_cruise_helper.update_v_cruise(CS, self.sm['carControl'].enabled, self.is_metric)
     if self.sm['carControl'].enabled and not self.CC_prev.enabled:
-      self.v_cruise_helper.initialize_v_cruise(CS, self.experimental_mode)
+      # Use CarState w/ buttons from the step selfdrived enables on
+      self.v_cruise_helper.initialize_v_cruise(self.CS_prev, self.experimental_mode)
 
     # TODO: mirror the carState.cruiseState struct?
     CS.vCruise = float(self.v_cruise_helper.v_cruise_kph)
@@ -249,6 +251,7 @@ def step(self):
       self.controls_update(CS, self.sm['carControl'])
 
     self.initialized_prev = initialized
+    self.CS_prev = CS
 
   def params_thread(self, evt):
     while not evt.is_set():