Add German (de), French (fr), Italian (it), and Swedish (sv) initial translations (#303)

webapp/src/lib/i18n.ts

@@ -11,7 +11,11 @@ export type Locale =
   | 'zh-TW'
   | 'ru'
   | 'es'
-  | 'fi';
+  | 'fi'
+  | 'de'
+  | 'fr'
+  | 'it'
+  | 'sv';
 
 import enMessages from './i18n/locales/en';
 const LOCALE_STORAGE_KEY = 'nodewarden.locale';
@@ -25,6 +29,10 @@ export const AVAILABLE_LOCALES: readonly { value: Locale; label: string }[] = [
   { value: 'ru', label: 'Русский' },
   { value: 'es', label: 'Español' },
   { value: 'fi', label: 'Suomi' },
+  { value: 'de', label: 'Deutsch' },
+  { value: 'fr', label: 'Français' },
+  { value: 'it', label: 'Italiano' },
+  { value: 'sv', label: 'Svenska' },
 ];
 
 let locale: Locale = resolveInitialLocale();
@@ -51,6 +59,10 @@ function resolveInitialLocale(): Locale {
       if (normalized.startsWith('ru')) return 'ru';
       if (normalized.startsWith('es')) return 'es';
       if (normalized.startsWith('fi')) return 'fi';
+      if (normalized.startsWith('de')) return 'de';
+      if (normalized.startsWith('fr')) return 'fr';
+      if (normalized.startsWith('it')) return 'it';
+      if (normalized.startsWith('sv')) return 'sv';
     }
   }
   return 'en';
@@ -63,6 +75,10 @@ const localeLoaders: Record<Locale, () => Promise<{ default: MessageTable }>> =
   ru: () => import('./i18n/locales/ru'),
   es: () => import('./i18n/locales/es'),
   fi: () => import('./i18n/locales/fi'),
+  de: () => import('./i18n/locales/de'),
+  fr: () => import('./i18n/locales/fr'),
+  it: () => import('./i18n/locales/it'),
+  sv: () => import('./i18n/locales/sv'),
 };
 
 function localeToHtmlLang(value: Locale): string {