Add homepage tag discovery matrix

templates/base.html

@@ -10,8 +10,8 @@
   <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
   <link href="https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500;600&family=Inter:wght@400;500&family=Playfair+Display:ital,wght@0,600;0,700;1,500;1,600&display=swap" rel="stylesheet">
   <link rel="icon" href="{{ '/static/favicon.svg'|url }}" type="image/svg+xml">
-  <link rel="stylesheet" href="{{ '/static/style.css'|url }}?v=23">
-  <script src="{{ '/static/tags.js'|url }}?v=1" defer></script>
+  <link rel="stylesheet" href="{{ '/static/style.css'|url }}?v=24">
+  <script src="{{ '/static/tags.js'|url }}?v=2" defer></script>
   <script src="{{ '/static/activity.js'|url }}?v=1" defer></script>
   <script src="{{ '/static/hero-circuit.js'|url }}?v=2" defer></script>
   <script src="{{ '/static/section-heroes.js'|url }}?v=1" defer></script>

templates/home.html

@@ -181,3 +181,50 @@
     </div>
   </div>
 </section>
+
+{% set tracked_tags = site.get('/tags').children %}
+<section class="homepage-tag-section" aria-labelledby="homepage-tag-heading" data-tag-matrix>
+  <div class="shell">
+    <div class="homepage-tag-header">
+      <div>
+        <p class="eyebrow">Topic map</p>
+        <h2 id="homepage-tag-heading">Explore the Signal</h2>
+        <p>A map of the topics that keep surfacing across Labyricorn. Pick a signal and follow it deeper into the site.</p>
+      </div>
+      <p class="homepage-tag-readout"><span aria-hidden="true"></span>{{ tracked_tags.count() }} tracked topics across Labyricorn</p>
+    </div>
+
+    <nav class="tag-matrix" aria-label="Explore content by topic">
+      {% for tag in tracked_tags %}
+        {% set usage = namespace(count=0) %}
+        {% for section_id in ['projects', 'blog', 'articles'] %}
+          {% for item in site.query('/' ~ section_id) %}
+            {% set item_tags = item.taxonomy_tags if item._model == 'project' else item.tags %}
+            {% if tag._id in item_tags %}{% set usage.count = usage.count + 1 %}{% endif %}
+          {% endfor %}
+        {% endfor %}
+        {% for project in site.query('/projects') %}
+          {% if project._model == 'project' %}
+            {% set devlog = site.get(project.path ~ '/devlog') %}
+            {% if devlog %}
+              {% for entry in devlog.children %}
+                {% if tag._id in entry.topic_tag_slugs %}{% set usage.count = usage.count + 1 %}{% endif %}
+              {% endfor %}
+            {% endif %}
+          {% endif %}
+        {% endfor %}
+        {% set weight = 4 if usage.count >= 8 else (3 if usage.count >= 4 else (2 if usage.count >= 2 else 1)) %}
+        <a class="tag-matrix-link tag-matrix-level-{{ weight }}" href="{{ tag|url }}" rel="tag" data-tag-title="{{ tag.title }}" data-tag-summary="{{ tag.summary|striptags|trim }}">
+          <span class="tag-matrix-name">{{ tag.title }}</span>
+          <span class="tag-matrix-count" aria-hidden="true">{{ usage.count }}</span>
+          <span class="visually-hidden"> — {{ usage.count }} published {% if usage.count == 1 %}entry{% else %}entries{% endif %}</span>
+        </a>
+      {% endfor %}
+    </nav>
+
+    <div class="tag-matrix-summary" aria-live="polite" aria-atomic="true">
+      <span class="tag-matrix-summary-label">Tag Summary</span>
+      <p><strong data-tag-summary-title>Preview a topic</strong><span data-tag-summary-text>Hover or focus a topic to preview it. Select a topic to open its archive.</span></p>
+    </div>
+  </div>
+</section>