fix: Updates docs and verification to halt joining process.

When returning the error and showing to user not allowed screen we were not completely halting the prejoin operation when token verification fails on room join and the token is valid in general.

resources/prosody-plugins/mod_token_verification.lua

 end
 load_config();
 
+-- verify user and whether he is allowed to join a room based on the token information
 local function verify_user(session, stanza)
 	log("debug", "Session token: %s, session room: %s",
 		tostring(session.auth_token),
 	local user_jid = stanza.attr.from;
 	if is_admin(user_jid) then
 		log("debug", "Token not required from admin user: %s", user_jid);
-		return nil;
+		return true;
 	end
 
     log("debug",
     end
 	log("debug",
         "allowed: %s to enter/create room: %s", user_jid, stanza.attr.to);
+    return true;
 end
 
 module:hook("muc-room-pre-create", function(event)
 	local origin, stanza = event.origin, event.stanza;
 	log("debug", "pre create: %s %s", tostring(origin), tostring(stanza));
-	return verify_user(origin, stanza);
+    if not verify_user(origin, stanza) then
+        return true; -- Returning any value other than nil will halt processing of the event
+    end
 end);
 
 module:hook("muc-occupant-pre-join", function(event)
 	local origin, room, stanza = event.origin, event.room, event.stanza;
 	log("debug", "pre join: %s %s", tostring(room), tostring(stanza));
-	return verify_user(origin, stanza);
+    if not verify_user(origin, stanza) then
+        return true; -- Returning any value other than nil will halt processing of the event
+    end
 end);
 
 for event_name, method in pairs {