fix(rsc): fix findSourceMapURL on Windows

Author: hi-ogawa

packages/plugin-rsc/src/plugins/find-source-map-url.ts

@@ -6,6 +6,7 @@ import {
   type ViteDevServer,
 } from 'vite'
 import fs from 'node:fs'
+import { slash } from './vite-utils'
 
 //
 // support findSourceMapURL
@@ -52,7 +53,7 @@ async function findSourceMapURL(
 ): Promise<object | undefined> {
   // this is likely server external (i.e. outside of Vite processing)
   if (filename.startsWith('file://')) {
-    filename = fileURLToPath(filename)
+    filename = slash(fileURLToPath(filename))
     if (
       isFileLoadingAllowed(server.config, filename) &&
       fs.existsSync(filename)