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/@nodelib/fs.walk/out/index.js

@@ -0,0 +1,34 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.Settings = exports.walkStream = exports.walkSync = exports.walk = void 0;
+const async_1 = require("./providers/async");
+const stream_1 = require("./providers/stream");
+const sync_1 = require("./providers/sync");
+const settings_1 = require("./settings");
+exports.Settings = settings_1.default;
+function walk(directory, optionsOrSettingsOrCallback, callback) {
+    if (typeof optionsOrSettingsOrCallback === 'function') {
+        new async_1.default(directory, getSettings()).read(optionsOrSettingsOrCallback);
+        return;
+    }
+    new async_1.default(directory, getSettings(optionsOrSettingsOrCallback)).read(callback);
+}
+exports.walk = walk;
+function walkSync(directory, optionsOrSettings) {
+    const settings = getSettings(optionsOrSettings);
+    const provider = new sync_1.default(directory, settings);
+    return provider.read();
+}
+exports.walkSync = walkSync;
+function walkStream(directory, optionsOrSettings) {
+    const settings = getSettings(optionsOrSettings);
+    const provider = new stream_1.default(directory, settings);
+    return provider.read();
+}
+exports.walkStream = walkStream;
+function getSettings(settingsOrOptions = {}) {
+    if (settingsOrOptions instanceof settings_1.default) {
+        return settingsOrOptions;
+    }
+    return new settings_1.default(settingsOrOptions);
+}