fix(site): guard parseSocialLinks against malformed SITE_SOCIAL entries

Skip entries without a url field (split by | produced fewer than 2 parts)
instead of crashing with TypeError on url.includes().

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

_data/site.js

@@ -14,10 +14,10 @@ function parseSocialLinks(envVar) {
   if (!envVar) return [];
   return envVar.split(",").map((link) => {
     const [name, url, icon] = link.split("|").map((s) => s.trim());
-    // Bluesky requires "me atproto" for verification
+    if (!url) return null;
     const rel = url.includes("bsky.app") ? "me atproto" : "me";
     return { name, url, rel, icon: icon || name.toLowerCase() };
-  });
+  }).filter(Boolean);
 }
 
 // Get fediverse handle for fediverse:creator meta tag