fix: add og: meta tags via template override, enable GitHub Pages

- Add docs/overrides/main.html with og:type, og:title, og:description,
  og:url, og:site_name meta tags using MkDocs template variables
- Enable GitHub Pages (Source: GitHub Actions) via API
- Build passes clean with mkdocs build --strict

Fixes QA failures #5 and #6 from ISS-73

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: chuongld20

docs/overrides/main.html

@@ -0,0 +1,9 @@
+{% extends "base.html" %}
+
+{% block extrahead %}
+  <meta property="og:type" content="website">
+  <meta property="og:title" content="{{ page.title }} - {{ config.site_name }}">
+  <meta property="og:description" content="{{ config.site_description }}">
+  <meta property="og:url" content="{{ page.canonical_url }}">
+  <meta property="og:site_name" content="{{ config.site_name }}">
+{% endblock %}

mkdocs.yml

@@ -8,6 +8,7 @@ edit_uri: edit/main/docs/
 
 theme:
   name: material
+  custom_dir: docs/overrides
   palette:
     - media: "(prefers-color-scheme: light)"
       scheme: default