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>

themes/openbureau/layouts/_partials/8bit_cursor_v3.html

@@ -0,0 +1,77 @@
+
+<style>
+* { cursor: none !important; }
+body { min-height: 400px; display: flex; align-items: center; justify-content: center; flex-direction: column; gap: 2rem; font-family: monospace; }
+#cursor {
+  position: fixed;
+  pointer-events: none;
+  z-index: 9999;
+  image-rendering: pixelated;
+}
+.demo-box {
+  padding: 1.5rem 2rem;
+  border: 0.5px solid var(--color-border-tertiary);
+  border-radius: 8px;
+  text-align: center;
+  font-size: 14px;
+  color: var(--color-text-secondary);
+}
+</style>
+
+<h2 class="sr-only">8-bit cursor preview</h2>
+<div class="demo-box">bewege die maus hier</div>
+<canvas id="cursor"></canvas>
+
+<script>
+const canvas = document.getElementById('cursor');
+const ctx = canvas.getContext('2d');
+const P = 3;
+
+// B=black, W=white, _=transparent
+// Pixel-genaue Nachzeichnung des klassischen Windows-Cursors
+const grid = [
+  'B_____________',
+  'BB____________',
+  'BWB___________',
+  'BWWB__________',
+  'BWWWB_________',
+  'BWWWWB________',
+  'BWWWWWB_______',
+  'BWWWWWWB______',
+  'BWWWWWWWB_____',
+  'BWWWWWWWWB____',
+  'BWWWWWWWWWB___',
+  'BWWWWWWBBB____',
+  'BWWWBWWB______',
+  'BWWB_BWWB_____',
+  'BWB___BWWB____',
+  'BB_____BWWB___',
+  'B_______BWB___',
+  '________BB____',
+];
+
+const rows = grid.length;
+const cols = grid[0].length;
+canvas.width = cols * P;
+canvas.height = rows * P;
+canvas.style.width = cols * P + 'px';
+canvas.style.height = rows * P + 'px';
+
+grid.forEach((row, y) => {
+  for (let x = 0; x < row.length; x++) {
+    const c = row[x];
+    if (c === 'B') {
+      ctx.fillStyle = '#000000';
+      ctx.fillRect(x * P, y * P, P, P);
+    } else if (c === 'W') {
+      ctx.fillStyle = '#ffffff';
+      ctx.fillRect(x * P, y * P, P, P);
+    }
+  }
+});
+
+document.addEventListener('mousemove', e => {
+  canvas.style.left = e.clientX + 'px';
+  canvas.style.top = e.clientY + 'px';
+});
+</script>