feat(karakeep): bookmark fetch client

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/karakeep/client.js

@@ -0,0 +1,11 @@
+export async function getBookmark(id) {
+  const base = process.env.KARAKEEP_API_URL || 'https://karakeep.hynesy.com';
+  const tok = process.env.KARAKEEP_API_TOKEN || '';
+  const res = await fetch(`${base}/api/v1/bookmarks/${encodeURIComponent(id)}`, {
+    headers: { Authorization: 'Bearer ' + tok },
+    signal: AbortSignal.timeout(10_000)
+  });
+  if (res.status === 404) return null;
+  if (!res.ok) throw new Error(`karakeep ${res.status}`);
+  return res.json();
+}