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/composables/useLanding.ts

@@ -2,22 +2,14 @@ import { computed } from 'vue'
 import { COPY, type Lang } from '~/utils/landingCopy'
 import { makeTheme } from '~/utils/landingTokens'
 
-// Shared landing state. `lang` is a real production toggle (da/en, both fully
-// translated). `dark` is kept as machinery from the design's Tweaks panel but
-// defaults to light — the primary theme the user landed on — and no toggle is
-// surfaced. Flip the default (or add a control) to enable dark later.
-
-// Language choice persists in the first-party `dezky-lang` cookie (see the
-// cookie policy). useState stays the reactive source of truth so a toggle in
-// one component updates the whole page live; we seed it from the cookie on SSR
-// init (so a reload keeps the chosen language) and write the cookie on change.
-const LANG_COOKIE = 'dezky-lang'
-const LANG_MAX_AGE = 60 * 60 * 24 * 365 // 12 months
-
-export const useLang = () => useState<Lang>('dz-lang', () => {
-  const saved = useCookie<Lang>(LANG_COOKIE).value
-  return saved === 'en' ? 'en' : 'da'
-})
+// Locale is owned by @nuxtjs/i18n (URL-based: English at /, Danish at /da, with
+// cookie-remembered browser detection). useLang exposes it as the 'da' | 'en'
+// the COPY object expects; useCopy maps to the matching translations. `dark` is
+// unused machinery from the design's Tweaks panel (the site is light-only).
+export const useLang = () => {
+  const { locale } = useI18n()
+  return computed<Lang>(() => (locale.value === 'da' ? 'da' : 'en'))
+}
 export const useDark = () => useState<boolean>('dz-dark', () => false)
 
 export const useTheme = () => {
@@ -26,16 +18,31 @@ export const useTheme = () => {
 }
 
 export const useCopy = () => {
-  const lang = useLang()
-  return computed(() => COPY[lang.value === 'en' ? 'en' : 'da'])
+  const { locale } = useI18n()
+  return computed(() => COPY[locale.value === 'da' ? 'da' : 'en'])
 }
 
-export function toggleLang() {
-  const lang = useLang()
-  const next: Lang = lang.value === 'da' ? 'en' : 'da'
-  lang.value = next
-  // Persist so the choice survives a reload / return visit.
-  useCookie<Lang>(LANG_COOKIE, { maxAge: LANG_MAX_AGE, sameSite: 'lax', path: '/' }).value = next
+// Setup-only. Returns a click handler that switches to the other locale's
+// localized route (flips the URL, e.g. / <-> /da).
+export function useLangToggle() {
+  const { locale } = useI18n()
+  const switchLocalePath = useSwitchLocalePath()
+  return () => navigateTo(switchLocalePath(locale.value === 'da' ? 'en' : 'da'))
+}
+
+// Setup-only. Localizes an internal href, preserving any #hash. Page links get
+// the locale prefix (/about -> /da/about in Danish); section anchors resolve
+// against the current locale's home (/#suite -> /da#suite). Bare #hash returns
+// unchanged (same-page anchor).
+export function useLocalizeHref() {
+  const localePath = useLocalePath()
+  return (href: string) => {
+    if (href.startsWith('#')) return href
+    const i = href.indexOf('#')
+    const path = i === -1 ? href : href.slice(0, i)
+    const hash = i === -1 ? '' : href.slice(i)
+    return localePath(path || '/') + hash
+  }
 }
 
 // Smooth-scroll to an in-page anchor, accounting for the sticky 72px nav.
@@ -48,18 +55,3 @@ export function scrollToAnchor(hash: string) {
   window.scrollTo({ top, behavior: 'smooth' })
   history.replaceState(null, '', hash)
 }
-
-// Navigate to a homepage section from anywhere. Footer/Nav links use the form
-// "/#suite": when already on the homepage we smooth-scroll in place; from a
-// sub-page we route home and index.vue scrolls to the hash on mount. Accepts
-// either "/#suite" or "#suite". Returns true if it handled the click (so the
-// caller can preventDefault), false to let normal navigation proceed.
-export function goToSection(href: string, currentPath: string): boolean {
-  const hash = href.slice(href.indexOf('#'))
-  if (currentPath === '/') {
-    scrollToAnchor(hash)
-    return true
-  }
-  navigateTo(`/${hash}`)
-  return true
-}