feat(control_plane): apply light standby hardware policy

components/domain/include/domain.h

@@ -227,6 +227,8 @@ int domain_get_rotate_speed_us(void);
  */
 esp_err_t domain_rotate_to_angle_with_timeout(float target_angle, int timeout_ms);
 esp_err_t domain_apply_rotation_delta(float delta);
+/** Release stepper holding current; the next movement re-energizes automatically. */
+esp_err_t domain_direction_release_motor_hold(int timeout_ms);
 void domain_set_calibration(const domain_direction_calibration_t *config);
 bool domain_get_calibration(domain_direction_calibration_t *out_config);
 /**
@@ -270,6 +272,8 @@ esp_err_t domain_runtime_multimodal_audio_start_uplink(
 esp_err_t domain_runtime_multimodal_audio_stop_uplink(int timeout_ms);
 bool domain_runtime_multimodal_audio_is_uplink_running(void);
 bool domain_runtime_multimodal_audio_is_initialized(void);
+/** Gate speaker output while preserving the microphone capture path. */
+esp_err_t domain_runtime_multimodal_audio_set_speaker_output_enabled(bool enabled);
 /**
  * @brief Start local MultiNet detection for the Chinese phrase "喵掌柜".
  *
@@ -608,6 +612,8 @@ esp_err_t domain_runtime_mini_program_provisioning_notify(
 esp_err_t domain_runtime_mini_program_provisioning_stop(int timeout_ms);
 
 esp_err_t domain_runtime_init_lcd_device(void);
+/** Set LCD backlight PWM brightness from 0 to 100 percent. */
+esp_err_t domain_runtime_set_lcd_backlight_brightness(uint8_t brightness_percent);
 void domain_runtime_start_lcd_render_loop(void);
 /**
  * @brief Stop LCD render loop with bounded teardown.