Remove tunnel_close acknowledgment to prevent SSL write failures

- Remove send_tunnel_close from handle_tunnel_close to avoid SSL errors
- When server sends tunnel_close, client just closes tunnel locally
- Prevents SSL connection corruption when trying to send on closed connection

wssshtools/tunnel.c

@@ -793,7 +793,7 @@ void send_tunnel_close(SSL *ssl, const char *request_id, int debug) {
     }
 }
 
-void handle_tunnel_close(SSL *ssl, const char *request_id, int debug) {
+void handle_tunnel_close(SSL *ssl __attribute__((unused)), const char *request_id, int debug) {
     pthread_mutex_lock(&tunnel_mutex);
     tunnel_t *tunnel = find_tunnel_by_request_id(request_id);
     if (tunnel) {
@@ -803,8 +803,6 @@ void handle_tunnel_close(SSL *ssl, const char *request_id, int debug) {
             printf("[DEBUG - Tunnel] Tunnel %s closed\n", request_id);
             fflush(stdout);
         }
-        // Send tunnel_close back to server to acknowledge
-        send_tunnel_close(ssl, request_id, debug);
     }
     pthread_mutex_unlock(&tunnel_mutex);
 }