ui: Headings kleiner + Library als Archiv-Zwilling (Sidebar weg)

- section-title 2.6→1.9rem max, 800→700; single-header h1 3→2.2rem max, 800→700;
  single-summary 1.4→1.2rem. Ruhiger, redaktioneller, site-weit.
- Library raus aus der zweispaltigen Sonderform: Übersicht = .atlas (gruppiert,
  wie Archiv-Root), Eintrag = .single (wie Essay) mit Quellen + Fuss
  (Gruppe · weitere Einträge · bearbeiten). library-nav-Partial entfernt.
- Voll CI-konform: Archiv und Library teilen jetzt dasselbe Gerüst.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

layouts/library/list.html

@@ -1,41 +1,31 @@
 {{ define "main" }}
-  <header class="section-header">
-    <h1 class="section-title">{{ .Title }}</h1>
-  </header>
+  {{ .Content }}
 
-  <div class="wiki">
-    <aside class="wiki-side">{{ partial "library-nav.html" . }}</aside>
+  {{ $pages := where site.RegularPages "Section" "library" }}
+  {{ $groups := dict }}
+  {{ range $pages }}
+    {{ $g := .Params.group | default "Allgemein" }}
+    {{ $existing := index $groups $g | default slice }}
+    {{ $groups = merge $groups (dict $g ($existing | append .)) }}
+  {{ end }}
 
-    <div class="wiki-page">
-      <div class="single-content">{{ .Content }}</div>
-
-      {{ $pages := where site.RegularPages "Section" "library" }}
-      {{ $groups := dict }}
-      {{ range $pages }}
-        {{ $g := .Params.group | default "Allgemein" }}
-        {{ $existing := index $groups $g | default slice }}
-        {{ $groups = merge $groups (dict $g ($existing | append .)) }}
+  {{ if $pages }}
+    <section class="atlas">
+      {{ range $g, $ps := $groups }}
+        <article class="atlas-section">
+          <h2>{{ $g }}</h2>
+          <ul class="atlas-list">
+            {{ range sort $ps "Title" }}
+              <li>
+                <a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a>
+                {{ with .Params.summary }}<span class="list-meta text-muted"> — {{ . }}</span>{{ end }}
+              </li>
+            {{ end }}
+          </ul>
+        </article>
       {{ end }}
-
-      {{ if $pages }}
-        <div class="wiki-index">
-          {{ range $g, $ps := $groups }}
-            <section class="wiki-group">
-              <h2>{{ $g }}</h2>
-              <ul>
-                {{ range sort $ps "Title" }}
-                  <li>
-                    <a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a>
-                    {{ with .Params.summary }}<span class="text-muted"> — {{ . }}</span>{{ end }}
-                  </li>
-                {{ end }}
-              </ul>
-            </section>
-          {{ end }}
-        </div>
-      {{ else }}
-        <p class="text-muted"><em>Noch keine Einträge — der erste entsteht im Redaktions-Editor.</em></p>
-      {{ end }}
-    </div>
-  </div>
+    </section>
+  {{ else }}
+    <p class="text-muted"><em>Noch keine Einträge — der erste entsteht im Redaktions-Editor.</em></p>
+  {{ end }}
 {{ end }}