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/gettext-parser/index.js

@@ -0,0 +1,16 @@
+'use strict';
+
+var poParser = require('./lib/poparser');
+
+module.exports = {
+  po: {
+    parse: poParser.parse,
+    createParseStream: poParser.stream,
+    compile: require('./lib/pocompiler')
+  },
+
+  mo: {
+    parse: require('./lib/moparser'),
+    compile: require('./lib/mocompiler')
+  }
+};