Add message when software watchdog stops motors

controller/src/logic.rs

@@ -143,6 +143,7 @@ pub async fn start_i2c_target(
                 if state.is_moving()
                     && current_millis() >= WATCHDOG_EXPIRATION.load(Ordering::Relaxed)
                 {
+                    defmt::debug!("stopping motors after watchdog has expired");
                     state.standby();
                 }
             });