fix(dev): handle critical CSS with absolute base and Vite Env API (#13598)

Co-authored-by: Mark Dalgleish <mark.john.dalgleish@gmail.com>

Author: chr33s

.changeset/cyan-cougars-trade.md

@@ -0,0 +1,5 @@
+---
+"@react-router/dev": patch
+---
+
+When `future.unstable_viteEnvironmentApi` is enabled and an absolute Vite `base` has been configured, ensure critical CSS is handled correctly during development

contributors.yml

@@ -66,6 +66,7 @@
 - chaance
 - chasinhues
 - chensokheng
+- chr33s
 - chrisngobanh
 - christopherchudzicki
 - ChristophP

packages/react-router-dev/vite/plugin.ts

@@ -1576,7 +1576,7 @@ export const reactRouterVitePlugin: ReactRouterVitePlugin = () => {
         if (ctx.reactRouterConfig.future.unstable_viteEnvironmentApi) {
           viteDevServer.middlewares.use(async (req, res, next) => {
             let [reqPathname, reqSearch] = (req.url ?? "").split("?");
-            if (reqPathname === `${ctx.publicPath}@react-router/critical.css`) {
+            if (reqPathname.endsWith("/@react-router/critical.css")) {
               let pathname = new URLSearchParams(reqSearch).get("pathname");
               if (!pathname) {
                 return next("No pathname provided");