feat(website): Umami analytics (conversion + CTA events)

Add the Umami tracker (cookieless, no consent banner) in the document head,
limited to the production hostnames via data-domains so dev traffic doesn't
pollute the stats. Pageviews are auto-tracked per page and locale.

Custom events on the key funnel:
- demo-request (demo form submit, with teamSize)
- partner-application (partner form submit, with type)
- book-demo (every "Book a demo" CTA click) via data-umami-event
- login (clicks through to the app)

Also fix the mobile nav menu links, which weren't localized (would drop
Danish visitors back to English).

apps/website/components/landing/ComingSoon.vue

@@ -13,6 +13,6 @@ const localePath = useLocalePath()
 <template>
   <LandingPageHeader :label="copy.pages.comingSoonKicker" :title="title" :intro="body" />
   <LandingContainer pad="clamp(32px, 5vw, 48px) clamp(20px, 5vw, 64px) clamp(56px, 8vw, 160px)">
-    <LandingBtn variant="primary" size="lg" @click="navigateTo(localePath('/demo'))">{{ copy.pages.ctaDemo }} →</LandingBtn>
+    <LandingBtn variant="primary" size="lg" data-umami-event="book-demo" @click="navigateTo(localePath('/demo'))">{{ copy.pages.ctaDemo }} →</LandingBtn>
   </LandingContainer>
 </template>