Add accelerometer deadzone via UART and ESP-NOW.

Filter BMA456 logs by configurable LSB threshold; master can set deadzone
for local sensor or slaves using ACCEL_DEADZONE (UART) and ESP-NOW broadcast
until unicast delivery is restored.

Co-authored-by: Cursor <cursoragent@cursor.com>

main/esp_now_proto.c

@@ -77,6 +77,16 @@ esp_err_t esp_now_proto_decode(const uint8_t *data, size_t len,
   return ESP_OK;
 }
 
+esp_err_t esp_now_proto_decode_with_mac(const uint8_t *data, size_t len,
+                                        alox_EspNowMessage *msg,
+                                        uint8_t mac_out[6]) {
+  if (mac_out == NULL) {
+    return ESP_ERR_INVALID_ARG;
+  }
+  esp_now_proto_setup_message_decode(msg, mac_out);
+  return esp_now_proto_decode(data, len, msg);
+}
+
 const alox_EspNowSlavePresence *
 esp_now_proto_get_presence(const alox_EspNowMessage *msg) {
   if (msg == NULL) {