feat(website): responsive / mobile layouts

Make the marketing site mobile-friendly across every page and section.
Desktop appearance is unchanged; all breakpoint logic targets <=768px.

- Fluid section padding via clamp(); equal grids use auto-fit/minmax,
  asymmetric grids stack to one column via scoped-CSS media queries
- Nav: real hamburger menu on mobile (links, lang toggle, login, CTA)
- ProductMockup: scales the whole dashboard to fit (zoom) instead of
  reflowing its internals into a tall stack
- Lower oversized heading clamp() minimums so titles no longer overflow
  at ~390px (hero, page headers, final CTA, brand cover/chapter)
- HowItWorks: row-gap when steps stack so node markers clear the text
- Compare + partners tables: stacked rows now label each value with its
  column (Dezky vs hyperscaler / CSP) instead of an ambiguous header
- Footer columns, tiers, calculator and tables stack cleanly on mobile

apps/website/components/landing/Container.vue

@@ -4,7 +4,7 @@ withDefaults(defineProps<{
   pad?: string
   max?: number
 }>(), {
-  pad: '120px 64px',
+  pad: 'clamp(56px, 8vw, 120px) clamp(20px, 5vw, 64px)',
   max: 1280,
 })
 </script>