fix(web): inline CSS stub loader for Vercel path resolution

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/css-stub-register.mjs

@@ -1,3 +1,10 @@
 import { register } from "node:module";
-import { pathToFileURL } from "node:url";
-register("./css-stub-loader.mjs", pathToFileURL("./"));
+register("data:text/javascript," + encodeURIComponent(`
+const STUB_EXT = ['.css', '.scss', '.sass', '.svg', '.png', '.jpg', '.jpeg', '.gif', '.ico', '.woff', '.woff2', '.ttf', '.eot'];
+export function resolve(specifier, context, nextResolve) {
+  if (STUB_EXT.some(ext => specifier.endsWith(ext))) {
+    return { url: 'data:text/javascript,export default ""', shortCircuit: true };
+  }
+  return nextResolve(specifier, context);
+}
+`));