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/stylelint/lib/rules/at-rule-property-required-list/index.js

@@ -0,0 +1,73 @@
+'use strict';
+
+const flattenArray = require('../../utils/flattenArray');
+const isStandardSyntaxAtRule = require('../../utils/isStandardSyntaxAtRule');
+const report = require('../../utils/report');
+const ruleMessages = require('../../utils/ruleMessages');
+const validateObjectWithArrayProps = require('../../utils/validateObjectWithArrayProps');
+const validateOptions = require('../../utils/validateOptions');
+const { isString } = require('../../utils/validateTypes');
+
+const ruleName = 'at-rule-property-required-list';
+
+const messages = ruleMessages(ruleName, {
+	expected: (property, atRule) => `Expected property "${property}" for at-rule "${atRule}"`,
+});
+
+const meta = {
+	url: 'https://stylelint.io/user-guide/rules/at-rule-property-required-list',
+};
+
+/** @type {import('stylelint').Rule<Record<string, string | string[]>>} */
+const rule = (primary) => {
+	return (root, result) => {
+		const validOptions = validateOptions(result, ruleName, {
+			actual: primary,
+			possible: [validateObjectWithArrayProps(isString)],
+		});
+
+		if (!validOptions) {
+			return;
+		}
+
+		root.walkAtRules((atRule) => {
+			if (!isStandardSyntaxAtRule(atRule)) {
+				return;
+			}
+
+			const { name, nodes } = atRule;
+			const atRuleName = name.toLowerCase();
+			const propList = flattenArray(primary[atRuleName]);
+
+			if (!propList) {
+				return;
+			}
+
+			for (const property of propList) {
+				const propertyName = property.toLowerCase();
+
+				const hasProperty = nodes.find(
+					(node) => node.type === 'decl' && node.prop.toLowerCase() === propertyName,
+				);
+
+				if (hasProperty) {
+					continue;
+				}
+
+				report({
+					message: messages.expected(propertyName, atRuleName),
+					node: atRule,
+					word: `@${atRule.name}`,
+					result,
+					ruleName,
+				});
+				continue;
+			}
+		});
+	};
+};
+
+rule.ruleName = ruleName;
+rule.messages = messages;
+rule.meta = meta;
+module.exports = rule;