Fix knip unused export warning for test utility function

Added @public JSDoc tag to disableHttp2() test utility function.
This function is intentionally exported for use in tests (see
tests/worker.test.ts) but knip's --production mode doesn't see
test file usage, causing a false positive unused export warning.

The @public tag tells knip this is an intentional public API.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

packages/react-on-rails-pro-node-renderer/src/worker.ts

@@ -92,7 +92,11 @@ function assertAsset(value: unknown, key: string): asserts value is Asset {
 // Remove after this issue is resolved: https://github.com/fastify/light-my-request/issues/315
 let useHttp2 = true;
 
-// Call before any test using `app.inject()`
+/**
+ * Test utility to disable HTTP/2 before calling `app.inject()`
+ * Workaround for https://github.com/fastify/light-my-request/issues/315
+ * @public
+ */
 export const disableHttp2 = () => {
   useHttp2 = false;
 };