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/irregular-plurals/readme.md

@@ -0,0 +1,38 @@
+# irregular-plurals
+
+> Map of nouns to their irregular plural form
+
+> An irregular plural in this library is defined as a noun that cannot be made plural by applying these rules:
+> - If the noun ends in an "s", "x", "z", "ch" or "sh", add "es"
+> - If the noun ends in a "y" and is preceded by a consonant, drop the "y" and add "ies"
+> - If the noun ends in a "y" and is preceded by a vowel, add "s"
+
+The list is just a [JSON file](irregular-plurals.json) and can be used anywhere.
+
+## Install
+
+```
+$ npm install irregular-plurals
+```
+
+## Usage
+
+```js
+const irregularPlurals = require('irregular-plurals');
+
+console.log(irregularPlurals.get('cactus'));
+//=> 'cacti'
+
+console.log(irregularPlurals);
+/*
+Map {
+	[addendum, 'addenda'],
+	[alga, 'algae'],
+	…
+}
+*/
+```
+
+## Related
+
+- [plur](https://github.com/sindresorhus/plur) - Pluralize a word