refactor(consolidate): IconButton + Badge-solid + @layer base + Massen-Migration

E: app.css Base-h1–h6 in @layer base → text-*!-Hacks in Titeln entfernt.
Neue Atoms: IconButton (runde Icon-Buttons), Badge solid-Variante + uppercase.

Migrationen (6 parallele Pässe):
- IconButton: 19 runde Nav/Close-Buttons (Carousel, Galleries, QuoteCarousel,
  PostOverview, Organisations, ImageModal).
- Badge: Kategorie/Status-Pills (PostCard, BlogOverview, kalender, Comments,
  CalendarBlock, FilesBlock, SearchableText, Stellingnahme).
- ui-Atome: Formular-Inputs (Comments, termin-melden, Stellingnahme) → TextInput/
  Textarea/Checkbox/SearchField; dunkle NewsletterInline bewusst raw.
- Button-Atom: ~20 inline Buttons in StellingnahmeGeneratorBlock.
- Radius-Sweep: Cards→rounded-lg (viele via .card-surface), Buttons/Inputs→rounded-md,
  Chips→rounded-full; StrommixBlock/Calendar/Files/Adressbuch u.a.

svelte-check 0 errors, voller Prod-Build grün.

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

src/lib/components/InfoCard.svelte

@@ -66,7 +66,7 @@
     <div class="flex gap-2.5">
       {#if icon}<div class="pt-px">{@render iconBadge("size-5", "size-3")}</div>{/if}
       <div class="flex min-w-0 flex-1 flex-col gap-2">
-        <h3 class="text-sm! font-bold! leading-[1.3]! tracking-[-0.01em] text-stein-800">{title}</h3>
+        <h3 class="text-sm font-bold leading-[1.3] tracking-[-0.01em] text-stein-800">{title}</h3>
         {#if description}
           <p class="line-clamp-3 text-[13px] font-normal leading-[1.45] text-stein-500">{description}</p>
         {/if}
@@ -80,8 +80,7 @@
   {:else}
     {#if icon}{@render iconBadge("size-11", "size-[23px]")}{/if}
     <div class="flex flex-col gap-1">
-      <!-- text-*! nötig: app.css setzt h3-Größe unlayered → Cascade-Layers. -->
-      <h3 class="text-base! font-bold! leading-[1.3]! tracking-[-0.01em] text-stein-800">{title}</h3>
+      <h3 class="text-base font-bold leading-[1.3] tracking-[-0.01em] text-stein-800">{title}</h3>
       {#if description}
         <p class="line-clamp-3 text-sm font-normal leading-[1.45] text-stein-500">{description}</p>
       {/if}