feat(web): add Discord link to sidebar account menu

Add a "Join our Discord" entry to the account dropdown's external-links
group, opening https://discord.gg/wdNEHETs87 in a new tab. lucide-react
has no Discord brand glyph, so include a small inline Discord SVG icon
(brand color). Add the joinDiscord label to all 8 locales.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/i18n/locales/ru-RU.ts

@@ -38,6 +38,7 @@ const ruRU = {
     helpDocs: 'Помощь',
     featureRequest: 'Запрос функции',
     starOnGitHub: 'Поставить звезду на GitHub',
+    joinDiscord: 'Присоединиться к Discord',
     create: 'Создать',
     edit: 'Редактировать',
     delete: 'Удалить',