feat: automatically detect language on server and translate UI (#530)

* feat: detect language on the server and translate page

* translate auth pages

* PR reviews

apps/dashboard/src/routes/+layout.ts

@@ -0,0 +1,28 @@
+import { config, loadTranslations } from '$lib/utils/functions/translations';
+import { profile } from '$lib/utils/store/user';
+import { get } from 'svelte/store';
+
+const SUPPORTED_LANGUAGES = config?.loaders?.map((loader) => loader.locale) || [];
+
+export const load = async ({ url, data }) => {
+  const { pathname } = url;
+
+  const profileStore = get(profile);
+
+  const serverLang = data.serverLang.split('-')[0];
+
+  const userLocale = profileStore.id ? profileStore.locale : getInitialLocale(serverLang);
+
+  const initLocale = getInitialLocale(userLocale);
+  await loadTranslations(initLocale, pathname); // keep this just before the `return`
+
+  return data;
+};
+
+function getInitialLocale(lang: string): string {
+  const locale = lang.split('-')[0];
+
+  if (SUPPORTED_LANGUAGES.includes(locale)) return locale;
+
+  return 'en';
+}