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/webpack/lib/javascript/JavascriptParserHelpers.js

@@ -0,0 +1,135 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const UnsupportedFeatureWarning = require("../UnsupportedFeatureWarning");
+const ConstDependency = require("../dependencies/ConstDependency");
+const BasicEvaluatedExpression = require("./BasicEvaluatedExpression");
+
+/** @typedef {import("estree").Expression} Expression */
+/** @typedef {import("estree").SourceLocation} SourceLocation */
+/** @typedef {import("./JavascriptParser")} JavascriptParser */
+/** @typedef {import("./JavascriptParser").Range} Range */
+/** @typedef {import("./BasicEvaluatedExpression").GetMembers} GetMembers */
+
+module.exports.approve = () => true;
+
+/**
+ * Returns plugin function.
+ * @param {boolean} value the boolean value
+ * @returns {(expression: Expression) => BasicEvaluatedExpression} plugin function
+ */
+module.exports.evaluateToBoolean = (value) =>
+	function booleanExpression(expr) {
+		return new BasicEvaluatedExpression()
+			.setBoolean(value)
+			.setRange(/** @type {Range} */ (expr.range));
+	};
+
+/**
+ * Returns callback.
+ * @param {string} identifier identifier
+ * @param {string} rootInfo rootInfo
+ * @param {GetMembers} getMembers getMembers
+ * @param {boolean | null=} truthy is truthy, null if nullish
+ * @returns {(expression: Expression) => BasicEvaluatedExpression} callback
+ */
+module.exports.evaluateToIdentifier = (
+	identifier,
+	rootInfo,
+	getMembers,
+	truthy
+) =>
+	function identifierExpression(expr) {
+		const evaluatedExpression = new BasicEvaluatedExpression()
+			.setIdentifier(identifier, rootInfo, getMembers)
+			.setSideEffects(false)
+			.setRange(/** @type {Range} */ (expr.range));
+		switch (truthy) {
+			case true:
+				evaluatedExpression.setTruthy();
+				break;
+			case null:
+				evaluatedExpression.setNullish(true);
+				break;
+			case false:
+				evaluatedExpression.setFalsy();
+				break;
+		}
+
+		return evaluatedExpression;
+	};
+
+/**
+ * Returns plugin function.
+ * @param {number} value the number value
+ * @returns {(expression: Expression) => BasicEvaluatedExpression} plugin function
+ */
+module.exports.evaluateToNumber = (value) =>
+	function stringExpression(expr) {
+		return new BasicEvaluatedExpression()
+			.setNumber(value)
+			.setRange(/** @type {Range} */ (expr.range));
+	};
+
+/**
+ * Returns plugin function.
+ * @param {string} value the string value
+ * @returns {(expression: Expression) => BasicEvaluatedExpression} plugin function
+ */
+module.exports.evaluateToString = (value) =>
+	function stringExpression(expr) {
+		return new BasicEvaluatedExpression()
+			.setString(value)
+			.setRange(/** @type {Range} */ (expr.range));
+	};
+
+/**
+ * Returns callback to handle unsupported expression.
+ * @param {JavascriptParser} parser the parser
+ * @param {string} message the message
+ * @returns {(expression: Expression) => boolean | undefined} callback to handle unsupported expression
+ */
+module.exports.expressionIsUnsupported = (parser, message) =>
+	function unsupportedExpression(expr) {
+		const dep = new ConstDependency(
+			"(void 0)",
+			/** @type {Range} */ (expr.range),
+			null
+		);
+		dep.loc = /** @type {SourceLocation} */ (expr.loc);
+		parser.state.module.addPresentationalDependency(dep);
+		if (!parser.state.module) return;
+		parser.state.module.addWarning(
+			new UnsupportedFeatureWarning(
+				message,
+				/** @type {SourceLocation} */ (expr.loc)
+			)
+		);
+		return true;
+	};
+
+module.exports.skipTraversal = () => true;
+
+/**
+ * Returns plugin function.
+ * @param {JavascriptParser} parser the parser
+ * @param {string} value the const value
+ * @param {(string[] | null)=} runtimeRequirements runtime requirements
+ * @returns {(expression: Expression) => true} plugin function
+ */
+module.exports.toConstantDependency = (parser, value, runtimeRequirements) =>
+	function constDependency(expr) {
+		const dep = new ConstDependency(
+			value,
+			/** @type {Range} */
+			(expr.range),
+			runtimeRequirements
+		);
+		dep.loc = /** @type {SourceLocation} */ (expr.loc);
+		parser.state.module.addPresentationalDependency(dep);
+		return true;
+	};