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/removeDimensions.js

@@ -0,0 +1,43 @@
+'use strict';
+
+exports.name = 'removeDimensions';
+exports.description =
+  'removes width and height in presence of viewBox (opposite to removeViewBox, disable it first)';
+
+/**
+ * Remove width/height attributes and add the viewBox attribute if it's missing
+ *
+ * @example
+ * <svg width="100" height="50" />
+ *   ↓
+ * <svg viewBox="0 0 100 50" />
+ *
+ * @author Benny Schudel
+ *
+ * @type {import('./plugins-types').Plugin<'removeDimensions'>}
+ */
+exports.fn = () => {
+  return {
+    element: {
+      enter: (node) => {
+        if (node.name === 'svg') {
+          if (node.attributes.viewBox != null) {
+            delete node.attributes.width;
+            delete node.attributes.height;
+          } else if (
+            node.attributes.width != null &&
+            node.attributes.height != null &&
+            Number.isNaN(Number(node.attributes.width)) === false &&
+            Number.isNaN(Number(node.attributes.height)) === false
+          ) {
+            const width = Number(node.attributes.width);
+            const height = Number(node.attributes.height);
+            node.attributes.viewBox = `0 0 ${width} ${height}`;
+            delete node.attributes.width;
+            delete node.attributes.height;
+          }
+        }
+      },
+    },
+  };
+};