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/comment-parser/es6/parser/spec-parser.js

@@ -0,0 +1,13 @@
+import { seedSpec } from '../util.js';
+export default function getParser({ tokenizers }) {
+    return function parseSpec(source) {
+        var _a;
+        let spec = seedSpec({ source });
+        for (const tokenize of tokenizers) {
+            spec = tokenize(spec);
+            if ((_a = spec.problems[spec.problems.length - 1]) === null || _a === void 0 ? void 0 : _a.critical)
+                break;
+        }
+        return spec;
+    };
+}