feature(library): Wiki-Links, Backlinks, Suche + A-Z-Index

single.html: [[Begriff]]-Auflösung zu internen Links (.wikilink),
fehlende Seiten als .wikilink-missing, „Siehe auch" (Gruppe+Tags)
und „Erwähnt in" (Backlinks), Eintrags-Fuss mit Gruppe + bearbeiten.

list.html: Suchfeld + A-Z-Index mit JS-Filter (Umlaute normalisiert),
data-title auf <li> für clientseitiges Filtern.

custom.css: .wikilink, .wikilink-missing, .entry-links, .entry-links-label,
.lib-filter, .lib-search, .lib-az — alle via --section-color (ichigo/rose).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

layouts/library/list.html

@@ -5,21 +5,47 @@
       {{ .Content }}
 
       {{ $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 }}
 
       {{ if $pages }}
+        {{/* A-Z Buchstaben aus vorhandenen Titeln */}}
+        {{ $letters := slice }}
+        {{ range $pages }}
+          {{ $first := substr (upper .Title) 0 1 }}
+          {{ $first = replace $first "Ä" "A" }}
+          {{ $first = replace $first "Ö" "O" }}
+          {{ $first = replace $first "Ü" "U" }}
+          {{ if not (in $letters $first) }}{{ $letters = $letters | append $first }}{{ end }}
+        {{ end }}
+        {{ $letters = sort $letters }}
+
+        <div class="lib-filter">
+          <input id="lib-search" class="lib-search" type="search" placeholder="Suchen …" autocomplete="off" spellcheck="false">
+          <div class="lib-az">
+            <button class="lib-az-all active" data-letter="">Alle</button>
+            {{ range $letters }}<button data-letter="{{ lower . }}">{{ . }}</button>{{ end }}
+          </div>
+        </div>
+
+        {{/* Gruppen aufbauen */}}
+        {{ $groups := dict }}
+        {{ range $pages }}
+          {{ $g := .Params.group | default "Allgemein" }}
+          {{ $existing := index $groups $g | default slice }}
+          {{ $groups = merge $groups (dict $g ($existing | append .)) }}
+        {{ end }}
+
         <section class="atlas">
           {{ range $g, $ps := $groups }}
             <article class="atlas-section">
               <h2>{{ $g }}</h2>
               <ul class="atlas-list">
                 {{ range sort $ps "Title" }}
-                  <li>
+                  {{ $norm := lower .Title }}
+                  {{ $norm = replace $norm "ä" "a" }}
+                  {{ $norm = replace $norm "ö" "o" }}
+                  {{ $norm = replace $norm "ü" "u" }}
+                  {{ $norm = replace $norm "ß" "ss" }}
+                  <li data-title="{{ $norm }}">
                     <a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a>
                     {{ with .Params.summary }}<span class="list-meta text-muted"> — {{ . }}</span>{{ end }}
                   </li>
@@ -28,6 +54,40 @@
             </article>
           {{ end }}
         </section>
+
+        <script>
+        (function(){
+          var input = document.getElementById('lib-search');
+          var azBtns = document.querySelectorAll('.lib-az button');
+          var activeLetter = '';
+
+          function filter() {
+            var q = input.value.trim().toLowerCase()
+              .replace(/ä/g,'a').replace(/ö/g,'o').replace(/ü/g,'u').replace(/ß/g,'ss');
+            document.querySelectorAll('.atlas-section').forEach(function(sec) {
+              var visible = 0;
+              sec.querySelectorAll('li[data-title]').forEach(function(li) {
+                var t = li.dataset.title;
+                var matchQ = !q || t.indexOf(q) !== -1;
+                var matchL = !activeLetter || t.charAt(0) === activeLetter;
+                if (matchQ && matchL) { li.style.display = ''; visible++; }
+                else li.style.display = 'none';
+              });
+              sec.style.display = visible ? '' : 'none';
+            });
+          }
+
+          input.addEventListener('input', filter);
+          azBtns.forEach(function(btn) {
+            btn.addEventListener('click', function() {
+              azBtns.forEach(function(b){ b.classList.remove('active'); });
+              this.classList.add('active');
+              activeLetter = this.dataset.letter || '';
+              filter();
+            });
+          });
+        })();
+        </script>
       {{ else }}
         <p class="text-muted"><em>Noch keine Einträge — der erste entsteht im Redaktions-Editor.</em></p>
       {{ end }}