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/@wordpress/data/build-module/utils/emitter.js

@@ -0,0 +1,42 @@
+/**
+ * Create an event emitter.
+ *
+ * @return {import("../types").DataEmitter} Emitter.
+ */
+export function createEmitter() {
+  let isPaused = false;
+  let isPending = false;
+  const listeners = new Set();
+  const notifyListeners = () =>
+  // We use Array.from to clone the listeners Set
+  // This ensures that we don't run a listener
+  // that was added as a response to another listener.
+  Array.from(listeners).forEach(listener => listener());
+  return {
+    get isPaused() {
+      return isPaused;
+    },
+    subscribe(listener) {
+      listeners.add(listener);
+      return () => listeners.delete(listener);
+    },
+    pause() {
+      isPaused = true;
+    },
+    resume() {
+      isPaused = false;
+      if (isPending) {
+        isPending = false;
+        notifyListeners();
+      }
+    },
+    emit() {
+      if (isPaused) {
+        isPending = true;
+        return;
+      }
+      notifyListeners();
+    }
+  };
+}
+//# sourceMappingURL=emitter.js.map

node_modules/@wordpress/data/build-module/utils/emitter.js.map

@@ -0,0 +1 @@
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