refactor(vd960DBN): tcp_json_srv data_json[2048] 宏化 → TCP_JSON_DATA_BUF_LEN(1024)

三处 char data_json[2048] (sensor_report×2 + loop_param_query×1)
改用头文件宏 TCP_JSON_DATA_BUF_LEN, 默认 1024。

容量核验: format_sensor_json 4通道~660B / format_loop_param_json~920B
均 < 1024, format 函数有 snprintf 溢出保护; 最终帧受 MAX_FRAME=800 截断。
附带: 栈上缓冲 2048→1024 每处省 1KB

vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/tcp_json_srv.c

@@ -829,7 +829,7 @@ static void json_sensor_callback(const uint8_t *pkg, uint16_t len)
         return;
     }
 
-    char data_json[2048];
+    char data_json[TCP_JSON_DATA_BUF_LEN];
     if (format_sensor_json(data_json, sizeof(data_json), &sr) == 0) {
         char *out = (char *)malloc(TCP_JSON_MAX_FRAME);
         if (out) {
@@ -1102,7 +1102,7 @@ static void json_check_pending(void) {
             memset(&pg, 0, sizeof(pg));
             int ret = lup_parse_param_get(g_lup_cmd.resp_buf, g_lup_cmd.resp_len, &pg);
             if (ret == 0) {
-                char data_json[2048];
+                char data_json[TCP_JSON_DATA_BUF_LEN];
                 if (format_loop_param_json(data_json, sizeof(data_json), &pg) == 0) {
                     json_send_ok(g_json_pending.socket, g_json_pending.msg_id,
                                  g_json_pending.cmd, data_json);
@@ -1319,7 +1319,7 @@ void tcp_json_push_sensor(void) {
         return;
     }
 
-    char data_json[2048];
+    char data_json[TCP_JSON_DATA_BUF_LEN];
     if (format_sensor_json(data_json, sizeof(data_json), &sr) == 0) {
         char *out = (char *)malloc(TCP_JSON_MAX_FRAME);
         if (out) {