Restore index.md content to fix GitHub Pages 404

The homepage was returning 404 because index.md was stripped of all content
in commit 4b07f87, leaving only front matter. Jekyll's home layout requires
actual content to render properly. Restored the original homepage content.

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

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

Author: SteveMacenski

index.md

@@ -1,4 +1,44 @@
 ---
 layout: home
 title: "Nav2 API Docs"
----
+---
+
+# Nav2 API Docs
+
+Welcome to the C++ developer-friendly Nav2 API documentation. This site provides comprehensive Doxygen-generated documentation for multiple Nav2 distributions because I (Your Friendly Neighborhood Navigator) find the new format utterly unreadable and I needed a new solution before my total descent into madness.
+
+## Available Distributions
+
+### Nav2 API Documentation
+
+<div class="distribution-grid">
+  {% assign sorted_nav2_distributions = site.nav2_distributions | sort: 'order' %}
+  {% for dist in sorted_nav2_distributions %}
+  <div class="distribution-card nav2-card">
+    <h3><a href="/nav2-{{ dist.slug }}/html/index.html">{{ dist.title }}</a></h3>
+    <p>{{ dist.description }}</p>
+    <p><strong>Status:</strong> {{ dist.status }}</p>
+  </div>
+  {% endfor %}
+</div>
+
+### ROS 2 API Documentation
+
+<div class="distribution-grid">
+  {% assign sorted_distributions = site.distributions | sort: 'order' %}
+  {% for dist in sorted_distributions %}
+  <div class="distribution-card">
+    <h3><a href="/{{ dist.slug }}/html/index.html">{{ dist.title }}</a></h3>
+    <p>{{ dist.description }}</p>
+    <p><strong>Status:</strong> {{ dist.status }}</p>
+  </div>
+  {% endfor %}
+</div>
+
+## Resources
+
+- [ROS 2 Official Documentation](https://docs.ros.org/)
+- [Rclcpp GitHub Repository](https://github.com/ros2/rclcpp)
+- [Nav2 GitHub Repository](https://github.com/ros-navigation/navigation2)
+- [Nav2 Project](https://nav2.org/)
+- [Nav2 Docs](https://docs.nav2.org/)