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/minimatch/dist/cjs/assert-valid-pattern.js

@@ -0,0 +1,14 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.assertValidPattern = void 0;
+const MAX_PATTERN_LENGTH = 1024 * 64;
+const assertValidPattern = (pattern) => {
+    if (typeof pattern !== 'string') {
+        throw new TypeError('invalid pattern');
+    }
+    if (pattern.length > MAX_PATTERN_LENGTH) {
+        throw new TypeError('pattern is too long');
+    }
+};
+exports.assertValidPattern = assertValidPattern;
+//# sourceMappingURL=assert-valid-pattern.js.map