feat: initialize Hugo static site with Bootstrap 5.x

Initialize minimal Hugo site structure with Bootstrap 5.3.2 integration for
markusgraf.ch conversion. Implements OpenSpec proposal add-minimal-hugo-site.

Features:
- Hugo project structure with standard directories
- Base layout template (baseof.html) with Bootstrap 5.3.2 via CDN
- Homepage (index.html) and single page (single.html) templates
- Reusable partials: header, footer, navigation
- Responsive Bootstrap grid layout
- Mobile-first design with semantic HTML5
- Valid HTML output with basic accessibility features
- Taxonomies disabled for minimal site (see docs/TAXONOMIES.md)

Documentation:
- IMPLEMENTATION_SUMMARY.md - Complete implementation guide
- docs/TAXONOMIES.md - Guide for re-enabling categories/tags
- static/README.md - Guide for placing static assets

Configuration:
- hugo.toml configured for markusgraf.ch
- .gitignore for Hugo build artifacts

All 24 tasks from OpenSpec proposal completed successfully.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

layouts/partials/nav.html

@@ -0,0 +1,12 @@
+<div class="collapse navbar-collapse" id="navbarNav">
+  <ul class="navbar-nav ms-auto">
+    <li class="nav-item">
+      <a class="nav-link{{ if .IsHome }} active{{ end }}" aria-current="page" href="{{ .Site.BaseURL }}">Home</a>
+    </li>
+    {{ range .Site.Menus.main }}
+    <li class="nav-item">
+      <a class="nav-link" href="{{ .URL }}">{{ .Name }}</a>
+    </li>
+    {{ end }}
+  </ul>
+</div>