style(design): consistency sweep + UX upgrades

- Palette: gray/zinc/slate/neutral → stein, red → fire, amber → erde,
  sky → himmel, green → wald
- Footer: replaced raw rgb with stein tokens
- Radius: unified to rounded-xs across cards, buttons, inputs, pagination
- Buttons: .btn-primary/.btn-secondary now font-medium; added secondary
- Card hover: -translate-y-0.5 + shadow + wald-300 border
- Header active link: wald border-bottom + wald-700 text
- Mobile nav: bigger touch targets + wald active accent
- Pagination: prev/next text labels + wald-500 active state with
  separated shape/color classes to avoid Tailwind conflicts
- Lead paragraph: scoped .markdown > p:first-child for top-level
  MarkdownBlock only via [data-block-type="markdown"]
- Section dividers: subtle wald-200 gradient between content rows
- Global focus-visible ring (wald-500)
- Inline hex → palette tokens (Badge amber, Tag custom-color contrast)
- Font weights snapped to design system (300/400/500/600/700)
- transition-all → transition-colors where only color changes
- Removed em-dashes from user-visible templates

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/lib/components/blocks/CalendarBlock.svelte

@@ -243,7 +243,7 @@
       <div class="flex items-center justify-between gap-2 mb-4">
         <button
           type="button"
-          class="p-2 rounded-md text-himmel-100 hover:bg-himmel-700 hover:text-himmel-50 transition-colors"
+          class="p-2 rounded-xs text-himmel-100 hover:bg-himmel-700 hover:text-himmel-50 transition-colors"
           aria-label={t(T.calendar_prev_month)}
           onclick={prevMonth}
         >
@@ -255,7 +255,7 @@
         >
         <button
           type="button"
-          class="p-2 rounded-md text-himmel-100 hover:bg-himmel-700 hover:text-himmel-50 transition-colors"
+          class="p-2 rounded-xs text-himmel-100 hover:bg-himmel-700 hover:text-himmel-50 transition-colors"
           aria-label={t(T.calendar_next_month)}
           onclick={nextMonth}
         >
@@ -280,7 +280,7 @@
             {#if hasEvents}
               <button
                 type="button"
-                class="relative aspect-square rounded-md flex flex-col items-center justify-center min-w-0 transition-colors cursor-pointer {isCurrentMonth
+                class="relative aspect-square rounded-xs flex flex-col items-center justify-center min-w-0 transition-colors cursor-pointer {isCurrentMonth
                   ? 'text-himmel-100 hover:bg-himmel-700'
                   : 'text-himmel-100 opacity-60 hover:opacity-80'} bg-himmel-700/50 font-semibold hover:bg-himmel-600 {isSelected
                   ? 'ring-2 ring-himmel-400 bg-himmel-600'
@@ -297,7 +297,7 @@
               </button>
             {:else}
               <div
-                class="relative aspect-square rounded-md flex flex-col items-center justify-center min-w-0 cursor-default {isCurrentMonth
+                class="relative aspect-square rounded-xs flex flex-col items-center justify-center min-w-0 cursor-default {isCurrentMonth
                   ? 'text-himmel-100'
                   : 'text-himmel-100 opacity-50'}"
               >