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/_partials/footer.html

@@ -0,0 +1,17 @@
+<div class="footer-grid">
+  <div class="footer-mark">OPENBUREAU</div>
+  <nav class="footer-nav" aria-label="Footer">
+    <ul>
+      <li><a href="/manifest/">Manifest</a></li>
+      <li><a href="/colophon/">Colophon</a></li>
+      <li><a href="https://openstudio.kgva.ch">Forum ↗</a></li>
+      <li><a href="https://gitea.kgva.ch">Code ↗</a></li>
+      <li><a href="/index.xml">RSS</a></li>
+    </ul>
+  </nav>
+  <p class="footer-tagline">
+    Sammlung, Plattform, Praxis.<br>
+    Texte unter <a href="https://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA 4.0</a>.
+  </p>
+  <p class="footer-credit">© {{ now.Year }} · Karim Gabriele Varano</p>
+</div>

layouts/_partials/head.html

@@ -0,0 +1,49 @@
+<meta charset="utf-8" />
+<meta name="viewport" content="width=device-width, initial-scale=1" />
+<meta name="color-scheme" content="light" />
+
+<title>{{ if .IsHome }}{{ site.Title | upper }}{{ else }}{{ printf "%s | %s" (.Title | upper) (site.Title | upper) }}{{ end }}</title>
+
+{{ with .Description | default site.Params.description }}<meta name="description" content="{{ . }}" />{{ end }}
+
+<link rel="canonical" href="{{ .Permalink }}" />
+
+{{/* Open Graph */}}
+<meta property="og:title" content="{{ .Title }}" />
+{{ with .Description | default site.Params.description }}<meta property="og:description" content="{{ . }}" />{{ end }}
+<meta property="og:type" content="{{ if .IsPage }}article{{ else }}website{{ end }}" />
+<meta property="og:url" content="{{ .Permalink }}" />
+{{ with site.Params.ogImage }}<meta property="og:image" content="{{ . | absURL }}" />{{ end }}
+
+{{/* Twitter Card */}}
+<meta name="twitter:card" content="summary" />
+<meta name="twitter:title" content="{{ .Title }}" />
+{{ with .Description | default site.Params.description }}<meta name="twitter:description" content="{{ . }}" />{{ end }}
+
+{{/* RSS */}}
+{{ with .OutputFormats.Get "rss" -}}
+  {{ printf `<link rel="%s" type="%s" href="%s" title="%s" />` .Rel .MediaType.Type .Permalink site.Title | safeHTML }}
+{{ end }}
+
+{{/* JSON-LD for articles */}}
+{{ if .IsPage }}
+<script type="application/ld+json">
+{
+  "@context": "https://schema.org",
+  "@type": "Article",
+  "headline": "{{ .Title }}",
+  "url": "{{ .Permalink }}",
+  "datePublished": "{{ .Date.Format "2006-01-02T15:04:05Z07:00" }}",
+  "dateModified": "{{ .Lastmod.Format "2006-01-02T15:04:05Z07:00" }}"
+  {{- with site.Params.author }},
+  "author": { "@type": "Person", "name": "{{ .name | default . }}" }
+  {{- end }}
+  {{- with $.Description | default site.Params.description }},
+  "description": "{{ . }}"
+  {{- end }}
+}
+</script>
+{{ end }}
+
+{{ partialCached "head/favicon.html" . }}
+{{ partialCached "head/css.html" . }}