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/createDeclarationIndexer.cjs

@@ -0,0 +1,34 @@
+'use strict';
+
+const cssTree = require('css-tree');
+
+class Index {
+    constructor() {
+        this.map = new Map();
+    }
+    resolve(str) {
+        let index = this.map.get(str);
+
+        if (index === undefined) {
+            index = this.map.size + 1;
+            this.map.set(str, index);
+        }
+
+        return index;
+    }
+}
+function createDeclarationIndexer() {
+    const ids = new Index();
+
+    return function markDeclaration(node) {
+        const id = cssTree.generate(node);
+
+        node.id = ids.resolve(id);
+        node.length = id.length;
+        node.fingerprint = null;
+
+        return node;
+    };
+}
+
+module.exports = createDeclarationIndexer;