fix: Enable stack canaries, heap poisoning, WDT panic; remove dead code

- CONFIG_COMPILER_STACK_CHECK_MODE_NORM=y (buffer overflow detection)
- CONFIG_HEAP_POISONING_LIGHT=y (use-after-free/corruption detection)
- CONFIG_ESP_TASK_WDT_PANIC=y (auto-reboot on hung task)
- Remove unused #include "esp_now.h" (CVE-2025-52471 mitigation)
- Replace hardcoded default IP 192.168.129.11 with 0.0.0.0 in Kconfig

get-started/csi_recv_router/main/app_main.c

@@ -28,7 +28,6 @@
 #include "esp_log.h"
 #include "esp_wifi.h"
 #include "esp_netif.h"
-#include "esp_now.h"
 #include "esp_timer.h"
 #include "esp_task_wdt.h"
 #include "esp_pm.h"
@@ -819,8 +818,12 @@ static void udp_socket_init(void)
     s_dest_addr.sin_port = htons(s_target_port);
     inet_pton(AF_INET, s_target_ip, &s_dest_addr.sin_addr);
 
-    ESP_LOGI(TAG, "UDP socket initialized, sending to %s:%d",
-             s_target_ip, s_target_port);
+    if (strcmp(s_target_ip, "0.0.0.0") == 0) {
+        ESP_LOGW(TAG, "No UDP target configured — use TARGET command to set destination");
+    } else {
+        ESP_LOGI(TAG, "UDP socket initialized, sending to %s:%d",
+                 s_target_ip, s_target_port);
+    }
 }
 
 /* --- Ping --- */