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/@sentry/utils/esm/error.js

@@ -0,0 +1,17 @@
+import { __extends } from "tslib";
+import { setPrototypeOf } from './polyfill';
+/** An error emitted by Sentry SDKs and related utilities. */
+var SentryError = /** @class */ (function (_super) {
+    __extends(SentryError, _super);
+    function SentryError(message) {
+        var _newTarget = this.constructor;
+        var _this = _super.call(this, message) || this;
+        _this.message = message;
+        _this.name = _newTarget.prototype.constructor.name;
+        setPrototypeOf(_this, _newTarget.prototype);
+        return _this;
+    }
+    return SentryError;
+}(Error));
+export { SentryError };
+//# sourceMappingURL=error.js.map