init: scaffold OPENBUREAU site with shibui-derived theme

- Hugo site for openbureau.ch (Deutsch, i18n-ready for EN/IT)
- Theme themes/openbureau/ = local copy of shibui, customized via
  site-level layouts and assets to keep the theme reference clean
- Editorial typography stack: Newsreader serif body, Space Grotesk
  display, Inter for listings, IBM Plex Mono for technical meta
- Content structure: library/ (Theorie, Büroführung, Software) with
  manifest and colophon at root; software is a library category, not
  a separate top-level
- Three views over one source: Journal (chronological home),
  Library (atlas grouped by section + tag cloud), single articles

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

layouts/library/list.html

@@ -0,0 +1,59 @@
+{{ define "main" }}
+  {{ .Content }}
+
+  {{ if .IsSection }}
+    {{ if eq .Path "/library" }}
+      {{/* Library root: Atlas — gruppiert nach Untersection */}}
+      <section class="atlas">
+        {{ range .Sections.ByWeight }}
+          <article class="atlas-section">
+            <h2><a href="{{ .RelPermalink }}">{{ .Title }}</a></h2>
+            {{ with .Params.description }}<p class="text-muted">{{ . }}</p>{{ end }}
+            <ul class="atlas-list">
+              {{ range first 6 .RegularPages.ByDate.Reverse }}
+                <li>
+                  <a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a>
+                  <span class="list-meta text-muted"> · {{ partial "date.html" .Date }}</span>
+                </li>
+              {{ end }}
+            </ul>
+            {{ if gt (len .RegularPages) 6 }}
+              <p class="more"><a href="{{ .RelPermalink }}">alle in {{ .Title }} →</a></p>
+            {{ end }}
+          </article>
+        {{ end }}
+
+        {{/* Tag-Cloud */}}
+        {{ with site.Taxonomies.tags }}
+          <article class="atlas-tags">
+            <h2>Tags</h2>
+            <ul class="tag-cloud">
+              {{ range $name, $taxonomy := . }}
+                <li><a href="/tags/{{ $name | urlize }}/">{{ $name }} <span class="text-muted">({{ len $taxonomy }})</span></a></li>
+              {{ end }}
+            </ul>
+          </article>
+        {{ end }}
+      </section>
+    {{ else }}
+      {{/* Library subsection: chronologisch */}}
+      <div class="time-list">
+        <ul>
+          {{ range .RegularPages.ByDate.Reverse }}
+            <li class="list-item">
+              <div class="list-title-row">
+                <div class="list-title">
+                  <a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a>
+                  {{ with .Params.summary }}
+                    <div class="list-summary text-muted">{{ . }}</div>
+                  {{ end }}
+                </div>
+                <div class="list-meta">{{ partial "date.html" .Date }}</div>
+              </div>
+            </li>
+          {{ end }}
+        </ul>
+      </div>
+    {{ end }}
+  {{ end }}
+{{ end }}