Add Plausible Analytics support

- Add plausible configuration option in _config.yml
- Create head-custom-plausible-analytics.html include file
- Update head-custom.html to include Plausible Analytics
- Support for self-hosted Plausible via plausible_script_url option

Users can now configure Plausible Analytics similarly to Google Analytics:
- Set plausible: yourdomain.com in _config.yml
- Optionally set plausible_script_url for self-hosted instances

_config.yml

@@ -2,4 +2,6 @@ title: Hacker theme
 description: Hacker is a theme for GitHub Pages.
 show_downloads: true
 google_analytics:
+plausible:
+# plausible_script_url: https://plausible.io/js/script.js  # Optional: for self-hosted Plausible instances
 theme: jekyll-theme-hacker

_includes/head-custom-plausible-analytics.html

@@ -0,0 +1,4 @@
+{% if site.plausible %}
+<!-- Plausible Analytics -->
+<script defer data-domain="{{ site.plausible }}" src="{% if site.plausible_script_url %}{{ site.plausible_script_url }}{% else %}https://plausible.io/js/script.js{% endif %}"></script>
+{% endif %}

_includes/head-custom.html

@@ -6,6 +6,9 @@
 <!-- Setup Google Analytics -->
 {% include head-custom-google-analytics.html %}
 
+<!-- Setup Plausible Analytics -->
+{% include head-custom-plausible-analytics.html %}
+
 <!-- You can set your favicon here -->
 <!-- link rel="shortcut icon" type="image/x-icon" href="{{ '/favicon.ico' | relative_url }}" -->