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/@nodelib/fs.stat/out/providers/sync.js

@@ -0,0 +1,23 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.read = void 0;
+function read(path, settings) {
+    const lstat = settings.fs.lstatSync(path);
+    if (!lstat.isSymbolicLink() || !settings.followSymbolicLink) {
+        return lstat;
+    }
+    try {
+        const stat = settings.fs.statSync(path);
+        if (settings.markSymbolicLink) {
+            stat.isSymbolicLink = () => true;
+        }
+        return stat;
+    }
+    catch (error) {
+        if (!settings.throwErrorOnBrokenSymbolicLink) {
+            return lstat;
+        }
+        throw error;
+    }
+}
+exports.read = read;