docs: refine social description

Author: brannn

docs/index.html

@@ -8,13 +8,13 @@
     <title>Threadmark - Continuity sidecar for Claude Code and Codex</title>
     <meta
       name="description"
-      content="Threadmark is a local continuity sidecar that gives Claude Code and Codex compact startup context when developers move between them in the same repository."
+      content="Threadmark is a local continuity sidecar for Claude Code and Codex, using continuous observation and checkpointing to preserve handoff context."
     >
     <link rel="canonical" href="https://thinkwright.github.io/threadmark/">
     <meta property="og:title" content="Threadmark - Continuity sidecar for Claude Code and Codex">
     <meta
       property="og:description"
-      content="Threadmark is a local continuity sidecar that gives Claude Code and Codex compact startup context when developers move between them in the same repository."
+      content="Threadmark is a local continuity sidecar for Claude Code and Codex, using continuous observation and checkpointing to preserve handoff context."
     >
     <meta property="og:type" content="website">
     <meta property="og:url" content="https://thinkwright.github.io/threadmark/">
@@ -26,7 +26,7 @@
     <meta name="twitter:title" content="Threadmark - Continuity sidecar for Claude Code and Codex">
     <meta
       name="twitter:description"
-      content="Threadmark is a local continuity sidecar that gives Claude Code and Codex compact startup context when developers move between them in the same repository."
+      content="Threadmark is a local continuity sidecar for Claude Code and Codex, using continuous observation and checkpointing to preserve handoff context."
     >
     <meta name="twitter:image" content="https://thinkwright.github.io/threadmark/assets/threadmark-og-1200x630.png">
     <!-- Google tag (gtag.js) -->