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/astral-regex/index.d.ts

@@ -0,0 +1,28 @@
+declare namespace astralRegex {
+	interface Options {
+		/**
+		Only match an exact string. Useful with `RegExp#test()` to check if a string is a astral symbol. Default: `false` _(Matches any astral symbols in a string)_
+		*/
+		readonly exact?: boolean;
+	}
+}
+
+/**
+Regular expression for matching [astral symbols](https://everything2.com/title/astral+plane).
+
+@returns A `RegExp` for matching astral symbols.
+
+@example
+```
+import astralRegex = require('astral-regex');
+
+astralRegex({exact: true}).test('🦄');
+//=> true
+
+'foo 🦄 💩 bar'.match(astralRegex());
+//=> ['🦄', '💩']
+```
+*/
+declare function astralRegex(options?: astralRegex.Options): RegExp;
+
+export = astralRegex;