Fix Elisp captcha compatibility

kkkmeet-server.el

@@ -135,7 +135,7 @@
 
 (defun kkkmeet-server--captcha-accepted-p (value)
   "Return non-nil when VALUE matches the configured captcha passphrase."
-  (string-equal-ignore-case (or value "") (kkkmeet-server--captcha-passphrase)))
+  (equal (downcase (or value "")) (downcase (kkkmeet-server--captcha-passphrase))))
 
 (defun kkkmeet-server--captcha-svg ()
   "Return an SVG captcha image for the configured passphrase."
@@ -396,9 +396,9 @@ When KEEP-OPEN is nil, close PROCESS after writing."
                  (clientId . ,safe-client-id)
                  (peers . ,peers)
                  (watchState . ,(or (gethash safe-room-id kkkmeet-server--watch-states)
-                                    :null))
+                                    nil))
                  (presentationState . ,(or (gethash safe-room-id kkkmeet-server--presentation-states)
-                                           :null))))
+                                           nil))))
       (kkkmeet-server--broadcast
        safe-room-id peer-id `((type . "peer-joined")
                               (peerId . ,peer-id)