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/csso/cjs/restructure/prepare/index.cjs

@@ -0,0 +1,45 @@
+'use strict';
+
+const cssTree = require('css-tree');
+const createDeclarationIndexer = require('./createDeclarationIndexer.cjs');
+const processSelector = require('./processSelector.cjs');
+
+function prepare(ast, options) {
+    const markDeclaration = createDeclarationIndexer();
+
+    cssTree.walk(ast, {
+        visit: 'Rule',
+        enter(node) {
+            node.block.children.forEach(markDeclaration);
+            processSelector(node, options.usage);
+        }
+    });
+
+    cssTree.walk(ast, {
+        visit: 'Atrule',
+        enter(node) {
+            if (node.prelude) {
+                node.prelude.id = null; // pre-init property to avoid multiple hidden class for generate
+                node.prelude.id = cssTree.generate(node.prelude);
+            }
+
+            // compare keyframe selectors by its values
+            // NOTE: still no clarification about problems with keyframes selector grouping (issue #197)
+            if (cssTree.keyword(node.name).basename === 'keyframes') {
+                node.block.avoidRulesMerge = true;  /* probably we don't need to prevent those merges for @keyframes
+                                                       TODO: need to be checked */
+                node.block.children.forEach(function(rule) {
+                    rule.prelude.children.forEach(function(simpleselector) {
+                        simpleselector.compareMarker = simpleselector.id;
+                    });
+                });
+            }
+        }
+    });
+
+    return {
+        declaration: markDeclaration
+    };
+}
+
+module.exports = prepare;