refactor(vd960DBN): replace compile-time NET_SSC/NET_JSON/NET_IOT macros with runtime g_sub_code_enable.iot_enable

- Remove NET_SSC_ENABLE, NET_JSON_ENABLE, NET_IOT_ENABLE from net_config.h
- Socket config always allocates max: 1 UDP + 2 TCP + 1 TCP_LISTEN
- All #if guards in net_srv.c/h and peripheral_main.c replaced with
  runtime g_sub_code_enable.iot_enable checks
- iot_enable=0 -> SSC mode (UDP + TCP client + JSON server)
- iot_enable=1 -> IoT MQTT mode (MQTT client via iot_mqtt_srv)

vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/peripheral_main.c

@@ -24,9 +24,7 @@
 #include "storage.h"
 #include "tcp_json_srv.h"
 #include "loop_uart_proto.h"
-#if NET_IOT_ENABLE
 #include "iot_mqtt_srv.h"
-#endif
 
 /*********************************************************************
  * GLOBAL TYPEDEFS
@@ -239,7 +237,6 @@ void Main_Circulation(void)
         }
         if(g_net_state.flag == 2)
         {
-#if NET_SSC_ENABLE
             if(g_sub_code_enable.iot_enable){
                 if(iot_net_info.mode == IOT_Addr_IP_Mode){
                     if(get_ipstr_to_array(iot_net_info.remote_addr, RemoteIP) == 0){
@@ -255,7 +252,6 @@ void Main_Circulation(void)
             {
                 WCHNET_CreateTcpSocket();                
             }
-#endif
         }
         
         
@@ -273,13 +269,13 @@ void Main_Circulation(void)
 
         poll_dbn_ble();
 
-#if NET_IOT_ENABLE
-        iot_mqtt_publish_sensor();  // Push 0xC0 sensor data to MQTT broker
-        iot_mqtt_poll();            // IoT MQTT state machine + heartbeat
-#else
-        tcp_json_push_sensor();     // Push 0xC0 sensor data to TCP JSON client
-        tcp_json_poll();
-#endif
+        if (g_sub_code_enable.iot_enable) {
+            iot_mqtt_publish_sensor();  // Push 0xC0 sensor data to MQTT broker
+            iot_mqtt_poll();            // IoT MQTT state machine + heartbeat
+        } else {
+            tcp_json_push_sensor();     // Push 0xC0 sensor data to TCP JSON client
+            tcp_json_poll();
+        }
 
         key_event_srv();
     }