Add BLE host transport selectable via DIP8 alongside UART.

Master can speak the same framed protobuf protocol over NimBLE or UART; goTool gains -ble, ble-rtt, and ble-stream timing checks for ESP-NOW coexistence.

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

main/cmd/cmd_ota.c

@@ -1,4 +1,5 @@
 #include "cmd_ota.h"
+#include "app_config.h"
 #include "led_ring.h"
 #include "ota_espnow.h"
 #include "ota_uart.h"
@@ -103,10 +104,24 @@ static void ota_prepare_task(void *param) {
   vTaskDelete(NULL);
 }
 
+static bool ota_host_is_uart(void) {
+  const app_config_t *cfg = app_config_get();
+  if (cfg != NULL && cfg->host_ble) {
+    ESP_LOGW(TAG, "OTA requires UART host (DIP8=0); BLE host active");
+    return false;
+  }
+  return true;
+}
+
 static void handle_ota_start(const uint8_t *data, size_t len) {
   alox_UartMessage uart_msg;
   alox_OtaStartPayload req = alox_OtaStartPayload_init_zero;
 
+  if (!ota_host_is_uart()) {
+    send_ota_failed(20);
+    return;
+  }
+
   if (uart_cmd_decode(data, len, &uart_msg) != ESP_OK) {
     send_ota_failed( 2);
     return;
@@ -334,6 +349,10 @@ static void ota_start_espnow_task(void *param) {
 }
 
 static void handle_ota_start_espnow(const uint8_t *data, size_t len) {
+  if (!ota_host_is_uart()) {
+    send_ota_failed(20);
+    return;
+  }
   (void)data;
   (void)len;