BLE Piezo 6채널 데이터 패킷 병합 (reb+red -> reb 단일 패킷)

- BLE_MTU_SIZE 240 -> 244 (ATT MTU 247 - 3 = 244, 기존 4B 낭비 해소)
- reb: 헤더 축소(14B → 6B) 후 데이터 병합 -> 119샘플까지 단일 패킷(현재 100샘플)
- reb: 헤더에서 peak_raw/peak_index/baseline_raw/버전마커 제거
  → PC에서 raw 데이터로 직접 계산, 단일 패킷이므로 버전마커 불필요
- 채널 간 딜레이 50ms -> 5ms (dr_binary_tx_safe 내부 재시도로 TX 보장)
- delta 전송(rdb/rdd)도 동일 방식 적용, 종료 패킷(ree:/rde:) 제거
- 채널 완료 판단: 종료 패킷(ree:) 제거, reb: 수신 시 채널 완료 (100샘플 기준 단일 패킷)
- 전체 완료는 기존과 동일하게 raa:로 판단

pc_firm/dr_adc121s051/dr_adc121s051.h

@@ -311,7 +311,7 @@ void dr_adc_print_buffer(const uint16_t *buffer, uint16_t num_samples);
  * @return dr_adc_err_t Error code
  *
  * @note Must call dr_adc_register_ble_tx() before using this function
- * @note BLE packets: reb: (header), red: (data), ree: (end)
+ * @note BLE packets: reb: (header+data merged), red: (continuation, >119 samples only)
  * @note Higher averaging reduces noise but increases measurement time (~0.3ms per avg)
  */
 dr_adc_err_t dr_adc_burst_capture_transmit(uint8_t freq_option, uint16_t delay_us,
@@ -345,9 +345,6 @@ void dr_piezo_select_channel(uint8_t channel);
 typedef struct {
     uint16_t samples[MAA_SAMPLES_MAX];  /**< Raw sample data */
     uint16_t num_samples;               /**< Actual sample count */
-    uint16_t peak_raw;                  /**< Peak amplitude */
-    uint16_t peak_index;                /**< Peak sample index */
-    uint16_t baseline_raw;              /**< Baseline level */
 } dr_maa_channel_t;
 
 /**
@@ -373,10 +370,11 @@ dr_adc_err_t dr_adc_capture_channel_only(uint8_t freq_option, uint16_t delay_us,
 /**
  * @brief Transmit captured channel data via BLE
  *
- * Sends previously captured channel data using reb:/red:/ree: protocol.
+ * Sends previously captured channel data using reb+red merged protocol.
+ * reb: tag(4) + num_samples(2) + data(up to 238B). red: only if > 119 samples.
  *
  * @param ch_data Pointer to captured channel data
- * @param ble_buffer Working buffer for BLE packets (>= 240 bytes)
+ * @param ble_buffer Working buffer for BLE packets (>= 244 bytes)
  * @return dr_adc_err_t Error code
  */
 dr_adc_err_t dr_adc_transmit_channel(const dr_maa_channel_t *ch_data,
@@ -410,7 +408,7 @@ dr_adc_err_t dr_adc_delta_compress(const uint16_t *samples, uint16_t num_samples
 /**
  * @brief Transmit captured channel data via BLE with delta compression
  *
- * Uses rdb:/rdd:/rde: protocol (delta variant of reb:/red:/ree:)
+ * Uses rdb+rdd merged protocol (delta variant of reb+red merged)
  *
  * @param ch_data Pointer to captured channel data
  * @param ble_buffer Working buffer for BLE packets (>= 240 bytes)
@@ -424,8 +422,8 @@ dr_adc_err_t dr_adc_transmit_channel_delta(const dr_maa_channel_t *ch_data,
  *
  * Design: State machine driven by BLE TX complete events
  * Flow:
- *   maa? cmd -> maa_async_start() -> capture CH0 -> TX reb: -> TX red: ...
- *   BLE_NUS_EVT_TX_RDY -> maa_async_continue() -> TX next packet or next channel
+ *   maa? cmd -> maa_async_start() -> capture all CH -> TX reb:(header+data) -> TX red: (if needed)
+ *   BLE_NUS_EVT_TX_RDY -> maa_async_on_tx_ready() -> TX next packet or next channel
  *   All done -> TX raa: -> state=IDLE
  *============================================================================*/
 
@@ -433,7 +431,7 @@ dr_adc_err_t dr_adc_transmit_channel_delta(const dr_maa_channel_t *ch_data,
 typedef enum {
     MAA_ASYNC_IDLE = 0,       /**< Not active */
     MAA_ASYNC_CAPTURING,      /**< ADC capture in progress */
-    MAA_ASYNC_TX_HEADER,      /**< Sending reb: header */
+    MAA_ASYNC_TX_HEADER,      /**< Sending reb: header+data merged */
     MAA_ASYNC_TX_DATA,        /**< Sending red: data packets */
     MAA_ASYNC_NEXT_CHANNEL,   /**< Preparing next channel */
     MAA_ASYNC_COMPLETE        /**< Sending raa: and finishing */
@@ -452,8 +450,6 @@ typedef struct {
     uint16_t    averaging;        /**< Averaging count */
     uint8_t    *ble_buffer;       /**< Working buffer for BLE packets */
     dr_maa_channel_t channels[MAA_NUM_CHANNELS]; /**< Captured data for each channel */
-    uint16_t    total_packets;    /**< Total packets for current channel */
-    uint16_t    data_packets;     /**< Data packets for current channel */
     bool        pre_capture_all;  /**< true: 전채널 캡처 완료 후 일괄 전송 (mbb용) */
     void      (*on_complete_cb)(void); /**< 비동기 캡처 완료 후 호출될 콜백 (NULL이면 미사용) */
 } maa_async_ctx_t;
@@ -469,7 +465,7 @@ typedef struct {
  * @param num_samples Samples per channel (1~200)
  * @param cycles Burst cycles (3~7)
  * @param averaging Averaging count (1~1000)
- * @param ble_buffer Working buffer (>= 240 bytes)
+ * @param ble_buffer Working buffer (>= 244 bytes)
  * @return dr_adc_err_t DR_ADC_OK if started successfully
  */
 dr_adc_err_t maa_async_start(uint8_t freq_option, uint16_t delay_us,