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/weak-set/add-all.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.weak-set');
+require('../../modules/esnext.weak-set.add-all');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('WeakSet', 'addAll');

node_modules/core-js/full/weak-set/delete-all.js

@@ -0,0 +1,6 @@
+'use strict';
+require('../../modules/es.weak-set');
+require('../../modules/esnext.weak-set.delete-all');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('WeakSet', 'deleteAll');

node_modules/core-js/full/weak-set/from.js

@@ -0,0 +1,12 @@
+'use strict';
+require('../../modules/es.object.to-string');
+require('../../modules/es.array.iterator');
+require('../../modules/es.string.iterator');
+require('../../modules/es.weak-set');
+require('../../modules/esnext.weak-set.from');
+require('../../modules/esnext.weak-set.add-all');
+require('../../modules/esnext.weak-set.delete-all');
+require('../../modules/web.dom-collections.iterator');
+var path = require('../../internals/path');
+
+module.exports = path.WeakSet.from;

node_modules/core-js/full/weak-set/index.js

@@ -0,0 +1,9 @@
+'use strict';
+var parent = require('../../actual/weak-set');
+require('../../modules/es.string.iterator');
+require('../../modules/esnext.weak-set.add-all');
+require('../../modules/esnext.weak-set.delete-all');
+require('../../modules/esnext.weak-set.from');
+require('../../modules/esnext.weak-set.of');
+
+module.exports = parent;

node_modules/core-js/full/weak-set/of.js

@@ -0,0 +1,10 @@
+'use strict';
+require('../../modules/es.object.to-string');
+require('../../modules/es.array.iterator');
+require('../../modules/es.weak-set');
+require('../../modules/esnext.weak-set.of');
+require('../../modules/esnext.weak-set.add-all');
+require('../../modules/esnext.weak-set.delete-all');
+var path = require('../../internals/path');
+
+module.exports = path.WeakSet.of;