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/svgo/plugins/cleanupAttrs.js

@@ -0,0 +1,49 @@
+'use strict';
+
+exports.name = 'cleanupAttrs';
+exports.description =
+  'cleanups attributes from newlines, trailing and repeating spaces';
+
+const regNewlinesNeedSpace = /(\S)\r?\n(\S)/g;
+const regNewlines = /\r?\n/g;
+const regSpaces = /\s{2,}/g;
+
+/**
+ * Cleanup attributes values from newlines, trailing and repeating spaces.
+ *
+ * @author Kir Belevich
+ *
+ * @type {import('./plugins-types').Plugin<'cleanupAttrs'>}
+ */
+exports.fn = (root, params) => {
+  const { newlines = true, trim = true, spaces = true } = params;
+  return {
+    element: {
+      enter: (node) => {
+        for (const name of Object.keys(node.attributes)) {
+          if (newlines) {
+            // new line which requires a space instead of themself
+            node.attributes[name] = node.attributes[name].replace(
+              regNewlinesNeedSpace,
+              (match, p1, p2) => p1 + ' ' + p2,
+            );
+            // simple new line
+            node.attributes[name] = node.attributes[name].replace(
+              regNewlines,
+              '',
+            );
+          }
+          if (trim) {
+            node.attributes[name] = node.attributes[name].trim();
+          }
+          if (spaces) {
+            node.attributes[name] = node.attributes[name].replace(
+              regSpaces,
+              ' ',
+            );
+          }
+        }
+      },
+    },
+  };
+};