fix(operator,portal): env-driven sign-out URLs + host labels (no more .local in prod)

Operator sign-out hardcoded the dev Authentik end-session URL, so prod
logout landed on auth.dezky.local. Mirror the portal's env-driven pattern
(NUXT_PUBLIC_AUTH_URL/NUXT_PUBLIC_OPERATOR_URL with .local fallbacks).
Expose authUrl/operatorUrl via public runtimeConfig and use them for the
Authentik admin links and the cosmetic host labels (sidebar, eyebrows,
auth-page hints). Portal: signed-out + webmail copy now derive their hosts
from runtime config (new public.mailUrl, NUXT_PUBLIC_MAIL_URL in prod).

apps/operator/pages/settings.vue

@@ -45,7 +45,7 @@ const lastSignIn = computed(() => {
   return new Date(iat * 1000)
 })
 
-const AUTHENTIK = 'https://auth.dezky.local'
+const AUTHENTIK = useRuntimeConfig().public.authUrl
 const links = [
   {
     icon: 'key' as const,