refactor: move personal site to sites/nrd.sh/

Reorganize for monorepo structure:
- Move content/, templates/, static/, site.toml → sites/nrd.sh/
- Frees root for sukr docs site
- Build with: sukr -c sites/nrd.sh/site.toml

sites/nrd.sh/templates/section/default.html

@@ -0,0 +1,13 @@
+{% extends "base.html" %} {% block content %}
+<h1>{{ section.title }}</h1>
+<ul class="item-list">
+  {% for item in items %}
+  <li>
+    <a href="./{{ item.slug }}.html">{{ item.frontmatter.title }}</a>
+    {% if item.frontmatter.description %}
+    <p>{{ item.frontmatter.description }}</p>
+    {% endif %}
+  </li>
+  {% endfor %}
+</ul>
+{% endblock content %}