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/runtime/CompatRuntimeModule.js

@@ -0,0 +1,85 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+*/
+
+"use strict";
+
+const RuntimeGlobals = require("../RuntimeGlobals");
+const RuntimeModule = require("../RuntimeModule");
+
+/** @typedef {import("../Chunk")} Chunk */
+/** @typedef {import("../ChunkGraph")} ChunkGraph */
+/** @typedef {import("../Compilation")} Compilation */
+
+class CompatRuntimeModule extends RuntimeModule {
+	constructor() {
+		super("compat", RuntimeModule.STAGE_ATTACH);
+		/** @type {boolean} */
+		this.fullHash = true;
+	}
+
+	/**
+	 * Generates runtime code for this runtime module.
+	 * @returns {string | null} runtime code
+	 */
+	generate() {
+		const compilation = /** @type {Compilation} */ (this.compilation);
+		const chunkGraph = /** @type {ChunkGraph} */ (this.chunkGraph);
+		const chunk = /** @type {Chunk} */ (this.chunk);
+		const {
+			runtimeTemplate,
+			mainTemplate,
+			moduleTemplates,
+			dependencyTemplates
+		} = compilation;
+		const bootstrap = mainTemplate.hooks.bootstrap.call(
+			"",
+			chunk,
+			compilation.hash || "XXXX",
+			moduleTemplates.javascript,
+			dependencyTemplates
+		);
+		const localVars = mainTemplate.hooks.localVars.call(
+			"",
+			chunk,
+			compilation.hash || "XXXX"
+		);
+		const requireExtensions = mainTemplate.hooks.requireExtensions.call(
+			"",
+			chunk,
+			compilation.hash || "XXXX"
+		);
+		const runtimeRequirements = chunkGraph.getTreeRuntimeRequirements(chunk);
+		let requireEnsure = "";
+		if (runtimeRequirements.has(RuntimeGlobals.ensureChunk)) {
+			const requireEnsureHandler = mainTemplate.hooks.requireEnsure.call(
+				"",
+				chunk,
+				compilation.hash || "XXXX",
+				"chunkId"
+			);
+			if (requireEnsureHandler) {
+				requireEnsure = `${
+					RuntimeGlobals.ensureChunkHandlers
+				}.compat = ${runtimeTemplate.basicFunction(
+					"chunkId, promises",
+					requireEnsureHandler
+				)};`;
+			}
+		}
+		return [bootstrap, localVars, requireEnsure, requireExtensions]
+			.filter(Boolean)
+			.join("\n");
+	}
+
+	/**
+	 * Returns true, if the runtime module should get it's own scope.
+	 * @returns {boolean} true, if the runtime module should get it's own scope
+	 */
+	shouldIsolate() {
+		// We avoid isolating this to have better backward-compat
+		return false;
+	}
+}
+
+module.exports = CompatRuntimeModule;