feat(website): bilingual i18n (English default, Danish at /da) + SEO

Add @nuxtjs/i18n: English is the default locale (no prefix), Danish lives
under /da (prefix_except_default). Both server-rendered and indexed with
hreflang alternates + per-locale canonical (useLocaleHead in app.vue).
First-visit browser language is auto-detected and remembered in the
i18n_redirected cookie (redirectOn root).

- Keep the hand-authored COPY object; useLang/useCopy now read the i18n
  locale; useLocalizeHref/useLangToggle added. Every internal link is
  localized so navigation stays in-locale.
- Clear segmented EN|DA language switcher (active segment filled) replacing
  the ambiguous "en · da" pill.
- SEO: useSeoMeta defaults are locale-aware; og:image switches per locale
  (English / Danish share card); favicon links; robots.txt + sitemap.xml;
  env-aware siteUrl/baseUrl (localhost in dev, dezky.eu in prod).
- Update the cookie policy (dezky-lang -> i18n_redirected).
- Gate the Traefik wss:443 HMR behind DEZKY_TRAEFIK so localhost dev/DevTools
  connect over plain ws (fixes the DevTools disconnect loop).

apps/website/components/landing/FinalCta.vue

@@ -4,6 +4,7 @@
 import { C } from '~/utils/landingTokens'
 import { useCopy } from '~/composables/useLanding'
 const copy = useCopy()
+const localePath = useLocalePath()
 </script>
 
 <template>
@@ -20,7 +21,7 @@ const copy = useCopy()
       </h2>
       <div :style="{ marginTop: '28px', maxWidth: 'min(100%, 520px)', fontFamily: '\'Inter\', sans-serif', fontSize: '19px', color: 'rgba(244,243,238,0.7)' }">{{ copy.finalCta.sub }}</div>
       <div :style="{ marginTop: '40px' }">
-        <button @click="navigateTo('/demo')" :style="{
+        <button @click="navigateTo(localePath('/demo'))" :style="{
           background: C.signal, color: C.carbon, border: 'none',
           padding: '20px 32px', fontFamily: '\'Inter\', sans-serif',
           fontSize: '16px', fontWeight: 600, borderRadius: '4px', cursor: 'pointer',