fix(react/testing-library): generate same snapshot for Windows (#1011)

## Summary

<!-- Can you explain the reasoning behind implementing this change? What
problem or issue does this pull request resolve? -->

Similar to #1007, we normalize the relative path to ensure consistent
snapshot generation across Windows, Linux, and macOS.

> [!NOTE]
> The testing library does not work on Windows now since we are using
`environment` with a absolute path.
> An error "Cannot find dependency
'vitest-environment-C:\Users\Admin\colin\lynx-stack\packages\react\testing-library\dist\env\vitest.js'"
would occur.
>
> I've submitted a fix at vitest-dev/vitest#8105

<!-- It would be helpful if you could provide any relevant context, such
as GitHub issues or related discussions. -->

issue: #81

## Checklist

<!--- Check and mark with an "x" -->

- [ ] Tests updated (or not required).
- [ ] Documentation updated (or not required).

Author: colinaaa

.changeset/shaggy-regions-sit.md

@@ -0,0 +1,3 @@
+---
+
+---

packages/react/testing-library/src/vitest.config.js

@@ -47,10 +47,10 @@ export const createVitestConfig = async (options) => {
           '@lynx-js/react/transform',
         );
         // relativePath should be stable between different runs with different cwd
-        const relativePath = path.relative(
+        const relativePath = normalizeSlashes(path.relative(
           __dirname,
           sourcePath,
-        );
+        ));
         const basename = path.basename(sourcePath);
         const result = transformReactLynxSync(sourceText, {
           mode: 'test',
@@ -123,3 +123,7 @@ export const createVitestConfig = async (options) => {
     },
   });
 };
+
+function normalizeSlashes(file) {
+  return file.replaceAll(path.win32.sep, '/');
+}