fix: Disable promiscuous mode on ESP32 — breaks CSI callback

Promiscuous mode (deauth/probe detection) disables CSI data collection
on original ESP32 at the driver level. Guard with #if !CONFIG_IDF_TARGET_ESP32
to only enable on newer chips where the two coexist.

get-started/csi_recv_router/main/app_main.c

@@ -1296,7 +1296,10 @@ void app_main()
 
     udp_socket_init();
     wifi_csi_init();
+#if !CONFIG_IDF_TARGET_ESP32
+    /* Promiscuous mode disables CSI on original ESP32 — only enable on newer chips */
     wifi_promiscuous_init();
+#endif
     wifi_ping_router_start();
 
     xTaskCreate(cmd_task, "cmd_task", 4096, NULL, 5, NULL);