feat(blocks): SectionGrid/InfoCard/ContactForm + Konsolidierung (Tier 1)

Neue Komponenten: SectionGrid, InfoCard (tone/compact), ArrowLink, ContactFormBlock,
SectionGridBlock. CMS-Blöcke section_grid + contact_form (info_card-Collection).
OrganisationsBlock: presentation "grid" (SectionGrid + InfoCard-Tiles).
Kontaktformular-Submit: size md + Send-Icon.

Konsolidierung Tier 1:
- .card-surface + Card-Atom → rounded-lg, .chip → rounded-full, Input-Atome → rounded-md
- tote .btn-*-Klassen aus app.css entfernt (Atom nutzt --color-btn-*-Tokens)
- hardcoded Hex → stein-Tokens (InfoCard, ContactFormBlock)
- redundante rounded-sm auf card-surface-Nutzern entfernt

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/components/ContactCard.svelte

@@ -16,7 +16,7 @@
 </script>
 
 <div
-  class="not-prose card-surface relative flex h-full min-w-0 flex-col gap-2 overflow-hidden rounded-sm p-4 transition-[transform,box-shadow,border-color] duration-200 hover:-translate-y-0.5 hover:border-wald-300 hover:shadow-md"
+  class="not-prose card-surface relative flex h-full min-w-0 flex-col gap-2 overflow-hidden p-4 transition-[transform,box-shadow,border-color] duration-200 hover:-translate-y-0.5 hover:border-wald-300 hover:shadow-md"
 >
   <div class="flex flex-col gap-1.5">
     <p class="truncate pr-6 text-sm font-medium leading-tight text-stein-900">{contact.name ?? ""}</p>