Improve review-tool performance.

web/vite.config.ts

@@ -13,6 +13,21 @@ const apiTarget = `http://127.0.0.1:${apiPort}`;
 export default defineConfig({
   plugins: [react()],
 
+  resolve: {
+    // The syntax highlighter runs in a worker (see src/lib/highlight.ts), and one
+    // package deep under refractor — decode-named-character-reference, pulled in
+    // by the markup language to decode HTML entities — ships a browser build
+    // that calls `document.createElement` at module scope. A worker has no
+    // document, so importing refractor there threw before a line was highlighted.
+    //
+    // The package publishes a document-free build for exactly this case and
+    // lists it first in its export map, under `worker`. Asking for that
+    // condition is what picks it up. It resolves for the main bundle too, which
+    // is what we want: it is the same function with a lookup table in place of
+    // the DOM's entity parser, and one implementation beats two.
+    conditions: ['worker'],
+  },
+
   // Relative asset URLs, because the page is served from a tab's path
   // (`/t/tab3/`) and not from the server root. With an absolute base the
   // browser would ask for `/assets/app.js` and get the tab router instead.