Add favicon, apple-touch-icon, and Open Graph social preview image

- favicon.ico (16/32/48px multi-size) for browser tabs
- apple-touch-icon.png (180px) for iOS home screen bookmarks
- og-image.png (1200x630) for social media link previews
- Layout template override injects OG meta tags and apple-touch-icon
- GitHub Pages base URL: bluedynamics.github.io/plone-pgcatalog/

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

Author: jensens

docs/sources/_static/apple-touch-icon.png

@@ -0,0 +1,13 @@
+{# Extend the theme's layout to inject apple-touch-icon and Open Graph meta #}
+{% extends "!layout.html" %}
+
+{% block metatags %}
+{{ super() }}
+<link rel="apple-touch-icon" sizes="180x180" href="{{ pathto('_static/apple-touch-icon.png', 1) }}">
+<meta property="og:type" content="website">
+<meta property="og:title" content="{{ title }}">
+<meta property="og:description" content="PostgreSQL-backed catalog for Plone, replacing ZCatalog BTrees with SQL queries on JSONB.">
+<meta property="og:image" content="https://bluedynamics.github.io/plone-pgcatalog/_static/og-image.png">
+<meta property="og:url" content="https://bluedynamics.github.io/plone-pgcatalog/">
+<meta name="twitter:card" content="summary_large_image">
+{% endblock %}

docs/sources/_static/favicon.ico

@@ -24,7 +24,7 @@
 
 myst_fence_as_directive = ["mermaid"]
 
-templates_path = []
+templates_path = ["_templates"]
 exclude_patterns = []
 
 # mermaid options
@@ -53,3 +53,4 @@
 
 html_static_path = ["_static"]
 html_logo = "_static/logo-web.png"
+html_favicon = "_static/favicon.ico"