perf: keep heavy work off UI thread

index.html

@@ -45,6 +45,8 @@
     <!-- Per-script Noto subsets, fetched lazily at runtime (one alphabet per
          file) so CAD text renders non-Latin scripts on the web. (#141) -->
     <link data-trunk rel="copy-dir" href="web/fonts" />
+    <link data-trunk rel="copy-file" href="web/ocs-parse-worker.js" />
+    <link data-trunk rel="copy-dir" href="web/worker_pkg" />
   </head>
   <body>
     <div id="loading">