test(scripts): make UI generator newline check deterministic

scripts/test-ui-reference-generation.mjs

@@ -42,6 +42,12 @@ try {
     cpSync(join(root, "packages", "ui", name), join(temporaryRoot, "packages", "ui", name));
   }
 
+  // Bring the isolated copy to the generator's canonical content before
+  // checking that a line-ending-only difference is preserved. The repository
+  // artifact can legitimately be stale while this script is proving the
+  // generator's newline behaviour.
+  runGenerator();
+
   const jsonFiles = ["component-catalog.json", "component-reference.json"];
   const before = new Map();
   for (const name of jsonFiles) {