feat: add OpenGraph and Twitter tags for sharing

Added opengraph.html partial with OpenGraph and Twitter meta tags for better
social sharing.

Author: zorexsalvo

static/img/pythonasia2026-banner.png

@@ -8,6 +8,8 @@
         <meta name="keywords" content="PythonAsia 2026">
         <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <meta name="description" content="PythonAsia 2026">
+        {% include 'opengraph.html' %}
+        <link rel="icon" type="image/x-icon" href="{% static 'img/py_kalinga-pot.png' %}">
         <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined" />
         <link rel="preconnect" href="https://fonts.googleapis.com">
         <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>

templates/base.html

@@ -0,0 +1,20 @@
+{% load static %}
+
+<!-- HTML Meta Tags -->
+<meta name="description" content="The flagship gathering for Python enthusiasts across Asia — uniting diverse communities across the region.">
+
+<!-- Facebook Meta Tags -->
+<meta property="og:url" content="https://2026.pythonasia.org">
+<meta property="og:type" content="website">
+<meta property="og:title" content="PythonAsia 2026">
+<meta property="og:description" content="The flagship gathering for Python enthusiasts across Asia — uniting diverse communities across the region.">
+<meta property="og:image" content="{% static 'img/pythonasia2026-banner.png' %}">
+
+<!-- X Meta Tags -->
+<meta name="twitter:card" content="summary_large_image">
+<meta property="twitter:domain" content="2026.pythonasia.org">
+<meta property="twitter:url" content="https://2026.pythonasia.org">
+<meta name="twitter:title" content="PythonAsia 2026">
+<meta name="twitter:description" content="The flagship gathering for Python enthusiasts across Asia — uniting diverse communities across the region.">
+<meta name="twitter:image" content="{% static 'img/pythonasia2026-banner.png' %}">
+