core: add server.lang to default fallback

packages/hydrooj/package.json

@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "3.14.3",
+    "version": "3.14.4",
     "bin": "bin/hydrooj.js",
     "main": "src/loader",
     "module": "src/loader",

packages/hydrooj/src/service/layers/renderer.ts

@@ -1,5 +1,6 @@
 import { ObjectID } from 'mongodb';
 import avatar from 'hydrooj/src/lib/avatar';
+import * as system from 'hydrooj/src/model/system';
 import type { KoaContext } from '../server';
 
 function serializer(k: string, v: any) {
@@ -65,7 +66,9 @@ export default (router, logger) => async (ctx: KoaContext, next) => {
     ctx.translate = (str: string) => {
         if (!str) return '';
         const lang = ctx.HydroContext.user?.viewLang || ctx.session?.viewLang;
-        return str.toString().translate(lang, ...ctx.acceptsLanguages());
+        return lang
+            ? str.toString().translate(lang, ...ctx.acceptsLanguages())
+            : str.toString().translate(...ctx.acceptsLanguages(), system.get('server.language'));
     };
     await next();
 };