fix: #9466, don't call leaveRoom in maintenance mode

public/src/app.js

@@ -231,7 +231,7 @@ app.cacheBuster = null;
 	};
 
 	app.leaveCurrentRoom = function () {
-		if (!socket) {
+		if (!socket || config.maintenanceMode) {
 			return;
 		}
 		var previousRoom = app.currentRoom;

src/controllers/api.js

@@ -27,6 +27,7 @@ apiController.loadConfig = async function (req) {
 		browserTitle: validator.escape(String(meta.config.browserTitle || meta.config.title || 'NodeBB')),
 		titleLayout: (meta.config.titleLayout || '{pageTitle} | {browserTitle}').replace(/{/g, '{').replace(/}/g, '}'),
 		showSiteTitle: meta.config.showSiteTitle === 1,
+		maintenanceMode: meta.config.maintenanceMode === 1,
 		minimumTitleLength: meta.config.minimumTitleLength,
 		maximumTitleLength: meta.config.maximumTitleLength,
 		minimumPostLength: meta.config.minimumPostLength,