fix: prevent asset conflicts between React and Grid.js versions

Add coexistence checks to all enqueue methods to prevent loading
both React and Grid.js assets simultaneously.

Changes:
- ReactAdmin.php: Only enqueue React assets when ?react=1
- Init.php: Skip Grid.js when React active on admin pages
- Form.php, Coupon.php, Access.php: Restore classic assets when ?react=0
- Customer.php, Product.php, License.php: Add coexistence checks

Now the toggle between Classic and React versions works correctly.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

node_modules/@hapi/hoek/README.md

@@ -0,0 +1,19 @@
+<a href="https://hapi.dev"><img src="https://raw.githubusercontent.com/hapijs/assets/master/images/family.png" width="180px" align="right" /></a>
+
+# @hapi/hoek
+
+#### Utility methods for the hapi ecosystem.
+
+**hoek** is part of the **hapi** ecosystem and was designed to work seamlessly with the [hapi web framework](https://hapi.dev) and its other components (but works great on its own or with other frameworks). If you are using a different web framework and find this module useful, check out [hapi](https://hapi.dev) – they work even better together.
+
+This module is not intended to solve every problem for everyone, but rather as a central place to store hapi-specific methods. If you're looking for a general purpose utility module, check out [lodash](https://github.com/lodash/lodash).
+
+### Visit the [hapi.dev](https://hapi.dev) Developer Portal for tutorials, documentation, and support
+
+## Useful resources
+
+- [Documentation and API](https://hapi.dev/family/hoek/)
+- [Version status](https://hapi.dev/resources/status/#hoek) (builds, dependencies, node versions, licenses, eol)
+- [Changelog](https://hapi.dev/family/hoek/changelog/)
+- [Project policies](https://hapi.dev/policies/)
+- [Free and commercial support options](https://hapi.dev/support/)