lgtm

frontend/src/i18n/index.ts

@@ -34,17 +34,31 @@ function getStoredLanguage(): LanguageCode | null {
   }
 }
 
+function getUrlLanguage(): LanguageCode | null {
+  try {
+    if (typeof window === 'undefined') return null;
+    const value = new URLSearchParams(window.location.search).get('lang');
+    return value ? toSupportedLanguage(value) : null;
+  } catch {
+    return null;
+  }
+}
+
 function getBrowserLanguages(): readonly string[] {
   if (typeof navigator === 'undefined') return [];
   return navigator.languages?.length ? navigator.languages : [navigator.language];
 }
 
 function detectLanguage(): LanguageCode {
-  // 1. Explicit user choice (persisted from the language dropdown)
+  // 1. Explicit URL language, used by generated screenshot/OG image URLs.
+  const urlLanguage = getUrlLanguage();
+  if (urlLanguage) return urlLanguage;
+
+  // 2. Explicit user choice (persisted from the language dropdown)
   const stored = getStoredLanguage();
   if (stored) return stored;
 
-  // 2. Browser preference (navigator.languages falls back to navigator.language)
+  // 3. Browser preference (navigator.languages falls back to navigator.language)
   for (const tag of getBrowserLanguages()) {
     const language = toSupportedLanguage(tag);
     if (language) return language;