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/Pricing.vue

@@ -4,6 +4,7 @@
 import { useTheme, useCopy } from '~/composables/useLanding'
 const t = useTheme()
 const copy = useCopy()
+const localePath = useLocalePath()
 </script>
 
 <template>
@@ -17,7 +18,7 @@ const copy = useCopy()
             <p :style="{ fontFamily: '\'Inter\', sans-serif', fontSize: '20px', lineHeight: 1.5, maxWidth: '640px', color: t.fgMuted, margin: 0, textWrap: 'pretty' }">{{ copy.pricing.lede }}</p>
           </div>
           <div :style="{ marginTop: '36px', display: 'flex', alignItems: 'center', gap: '16px' }">
-            <LandingBtn variant="primary" size="lg" @click="navigateTo('/demo')">{{ copy.pricing.cta }} →</LandingBtn>
+            <LandingBtn variant="primary" size="lg" @click="navigateTo(localePath('/demo'))">{{ copy.pricing.cta }} →</LandingBtn>
           </div>
         </div>
         <div :style="{ background: t.surface, border: `1px solid ${t.border}`, borderRadius: '6px', padding: '36px 36px' }">