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/es/set/difference.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.set');
+require('../../modules/es.set.difference.v2');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Set', 'difference');

node_modules/core-js/es/set/index.js

@@ -0,0 +1,15 @@
+'use strict';
+require('../../modules/es.array.iterator');
+require('../../modules/es.object.to-string');
+require('../../modules/es.set');
+require('../../modules/es.set.difference.v2');
+require('../../modules/es.set.intersection.v2');
+require('../../modules/es.set.is-disjoint-from.v2');
+require('../../modules/es.set.is-subset-of.v2');
+require('../../modules/es.set.is-superset-of.v2');
+require('../../modules/es.set.symmetric-difference.v2');
+require('../../modules/es.set.union.v2');
+require('../../modules/es.string.iterator');
+var path = require('../../internals/path');
+
+module.exports = path.Set;

node_modules/core-js/es/set/intersection.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.set');
+require('../../modules/es.set.intersection.v2');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Set', 'intersection');

node_modules/core-js/es/set/is-disjoint-from.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.set');
+require('../../modules/es.set.is-disjoint-from.v2');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Set', 'isDisjointFrom');

node_modules/core-js/es/set/is-subset-of.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.set');
+require('../../modules/es.set.is-subset-of.v2');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Set', 'isSubsetOf');

node_modules/core-js/es/set/is-superset-of.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.set');
+require('../../modules/es.set.is-superset-of.v2');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Set', 'isSupersetOf');

node_modules/core-js/es/set/symmetric-difference.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.set');
+require('../../modules/es.set.symmetric-difference.v2');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Set', 'symmetricDifference');

node_modules/core-js/es/set/union.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.set');
+require('../../modules/es.set.union.v2');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Set', 'union');