fix(ui): left panel layout and scroll, set default language to English

src/lib/i18n.tsx

@@ -173,6 +173,8 @@ export function I18nProvider({ children }: { children: ReactNode }) {
       const stored = localStorage.getItem('melodymuse-lang');
       if (stored === 'de' || stored === 'en') return stored;
     } catch {
+      // ignore
+    }
     return 'en';
   });