feat: separate NPM and Traefik settings tabs, add Events to sidebar nav

- Create /settings/npm page with NPM credentials + SSL certificate picker
- Create /settings/traefik page with entrypoint, cert resolver, network, API URL + labels reference
- Dynamic settings nav: NPM/Traefik tabs only visible when respective provider is selected
- Remove inline Traefik config from general settings page
- Remove old credentials page (replaced by NPM tab)
- Add Events page to sidebar navigation
- Fix SystemHealthCard after standalone proxy removal

web/src/lib/i18n/en.json

@@ -248,6 +248,10 @@
     "proxyNoneDesc": "No proxy — containers are accessed directly by port",
     "proxyNpm": "Nginx Proxy Manager",
     "proxyNpmDesc": "Routes managed via NPM API (configure credentials below)",
+    "npm": "Nginx Proxy Manager",
+    "traefik": "Traefik",
+    "traefikLabelsTitle": "Docker Labels Reference",
+    "traefikLabelsDesc": "These labels are automatically added to deployed containers. Shown here for reference.",
     "proxyTraefik": "Traefik",
     "proxyTraefikDesc": "Auto-discovery via Docker labels — no API calls needed",
     "proxyNoneWarning": "Switching to None does not remove existing proxy routes. You may need to clean them up manually.",

web/src/lib/i18n/ru.json

@@ -248,6 +248,10 @@
     "proxyNoneDesc": "Без прокси — контейнеры доступны напрямую по порту",
     "proxyNpm": "Nginx Proxy Manager",
     "proxyNpmDesc": "Маршруты через NPM API (настройте учётные данные ниже)",
+    "npm": "Nginx Proxy Manager",
+    "traefik": "Traefik",
+    "traefikLabelsTitle": "Справка по Docker-меткам",
+    "traefikLabelsDesc": "Эти метки автоматически добавляются к развёрнутым контейнерам. Показаны для справки.",
     "proxyTraefik": "Traefik",
     "proxyTraefikDesc": "Автообнаружение через Docker-метки — без API-вызовов",
     "proxyNoneWarning": "Переключение на «Нет» не удаляет существующие прокси-маршруты. Возможно, потребуется очистить их вручную.",