chore: tweak update ready notification wording

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

src/native/updater.ts

@@ -96,7 +96,7 @@ async function downloadAndInstall(url: string, version: string) {
     });
   });
 
-  const n = notify("Update Ready", `Sanctum ${version} is installed — click to restart.`);
+  const n = notify("Update Ready", `Sanctum ${version} is ready — click to restart.`);
   n.on("click", () => { app.relaunch(); app.exit(0); });
 }