feat: add Open Graph and Twitter meta tags for link previews

Adds OG and Twitter Card meta tags so sharing agent-workspace.ai
on Discord, Twitter/X, Slack etc shows a proper preview card with
title, description, and the og-card.png image.

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

Author: web3dev1337

site/index.html

@@ -5,6 +5,21 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>Agent Workspace | All Your Agents, One Workspace</title>
   <meta name="description" content="Run multiple CLI agents in parallel across different repos with complete local control. Claude Max and Codex plan compatible. Zero telemetry.">
+
+  <!-- Open Graph -->
+  <meta property="og:type" content="website">
+  <meta property="og:url" content="https://agent-workspace.ai">
+  <meta property="og:title" content="Agent Workspace | All Your Agents, One Workspace">
+  <meta property="og:description" content="Run multiple CLI agents in parallel across different repos. Your hardware, your plans, your API keys. Zero telemetry.">
+  <meta property="og:image" content="https://agent-workspace.ai/assets/og-card.png">
+
+  <!-- Twitter / X -->
+  <meta name="twitter:card" content="summary_large_image">
+  <meta name="twitter:url" content="https://agent-workspace.ai">
+  <meta name="twitter:title" content="Agent Workspace | All Your Agents, One Workspace">
+  <meta name="twitter:description" content="Run multiple CLI agents in parallel across different repos. Your hardware, your plans, your API keys. Zero telemetry.">
+  <meta name="twitter:image" content="https://agent-workspace.ai/assets/og-card.png">
+
   <link rel="icon" href="assets/favicon.svg" type="image/svg+xml">
   <link rel="preconnect" href="https://fonts.googleapis.com">
   <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>