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/core-js/full/date/get-year.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date/get-year');
+
+module.exports = parent;

node_modules/core-js/full/date/index.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date');
+
+module.exports = parent;

node_modules/core-js/full/date/now.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date/now');
+
+module.exports = parent;

node_modules/core-js/full/date/set-year.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date/set-year');
+
+module.exports = parent;

node_modules/core-js/full/date/to-gmt-string.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date/to-gmt-string');
+
+module.exports = parent;

node_modules/core-js/full/date/to-iso-string.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date/to-iso-string');
+
+module.exports = parent;

node_modules/core-js/full/date/to-json.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date/to-json');
+
+module.exports = parent;

node_modules/core-js/full/date/to-primitive.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date/to-primitive');
+
+module.exports = parent;

node_modules/core-js/full/date/to-string.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../actual/date/to-string');
+
+module.exports = parent;