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/cssstyle/lib/properties/font.js

@@ -0,0 +1,43 @@
+'use strict';
+
+var TYPES = require('../parsers').TYPES;
+var valueType = require('../parsers').valueType;
+var shorthandParser = require('../parsers').shorthandParser;
+var shorthandSetter = require('../parsers').shorthandSetter;
+var shorthandGetter = require('../parsers').shorthandGetter;
+
+var shorthand_for = {
+  'font-family': require('./fontFamily'),
+  'font-size': require('./fontSize'),
+  'font-style': require('./fontStyle'),
+  'font-variant': require('./fontVariant'),
+  'font-weight': require('./fontWeight'),
+  'line-height': require('./lineHeight'),
+};
+
+var static_fonts = [
+  'caption',
+  'icon',
+  'menu',
+  'message-box',
+  'small-caption',
+  'status-bar',
+  'inherit',
+];
+
+var setter = shorthandSetter('font', shorthand_for);
+
+module.exports.definition = {
+  set: function(v) {
+    var short = shorthandParser(v, shorthand_for);
+    if (short !== undefined) {
+      return setter.call(this, v);
+    }
+    if (valueType(v) === TYPES.KEYWORD && static_fonts.indexOf(v.toLowerCase()) !== -1) {
+      this._setProperty('font', v);
+    }
+  },
+  get: shorthandGetter('font', shorthand_for),
+  enumerable: true,
+  configurable: true,
+};