Add favicon and thumbnails for landing page

Author: mheadd

.gitignore

@@ -0,0 +1 @@
+node_modules/

docs/favicon-16.png

@@ -5,6 +5,25 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <meta name="description" content="SpecOps: Specification-Driven Legacy System Modernization - Using AI to preserve institutional knowledge while modernizing government systems">
     <title>SpecOps: Specification-Driven Legacy Modernization</title>
+    <!-- Icons -->
+    <link rel="icon" type="image/svg+xml" href="./favicon.svg">
+    <link rel="icon" type="image/png" sizes="32x32" href="./favicon-32.png">
+    <link rel="icon" type="image/png" sizes="16x16" href="./favicon-16.png">
+    <link rel="mask-icon" href="./safari-pinned-tab.svg" color="#2563eb">
+    <link rel="apple-touch-icon" sizes="180x180" href="./icon-180.png">
+    <meta name="theme-color" content="#2563eb">
+
+    <!-- Open Graph / Twitter -->
+    <meta property="og:type" content="website">
+    <meta property="og:title" content="SpecOps: Specification-Driven Legacy Modernization">
+    <meta property="og:description" content="Specifications over code. Preserve institutional knowledge, verify behavior, and generate modern systems with AI.">
+    <meta property="og:image" content="./og-image.png">
+    <meta property="og:image:width" content="1200">
+    <meta property="og:image:height" content="630">
+    <meta name="twitter:card" content="summary_large_image">
+    <meta name="twitter:title" content="SpecOps: Specification-Driven Legacy Modernization">
+    <meta name="twitter:description" content="Specifications over code. Preserve institutional knowledge, verify behavior, and generate modern systems with AI.">
+    <meta name="twitter:image" content="./og-image.png">
     <style>
         * {
             margin: 0;