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/date-fns/esm/startOfSecond/index.d.ts

@@ -0,0 +1,4 @@
+// This file is generated automatically by `scripts/build/typings.js`. Please, don't change it.
+
+import { startOfSecond } from 'date-fns'
+export default startOfSecond

node_modules/date-fns/esm/startOfSecond/index.js

@@ -0,0 +1,26 @@
+import toDate from "../toDate/index.js";
+import requiredArgs from "../_lib/requiredArgs/index.js";
+/**
+ * @name startOfSecond
+ * @category Second Helpers
+ * @summary Return the start of a second for the given date.
+ *
+ * @description
+ * Return the start of a second for the given date.
+ * The result will be in the local timezone.
+ *
+ * @param {Date|Number} date - the original date
+ * @returns {Date} the start of a second
+ * @throws {TypeError} 1 argument required
+ *
+ * @example
+ * // The start of a second for 1 December 2014 22:15:45.400:
+ * const result = startOfSecond(new Date(2014, 11, 1, 22, 15, 45, 400))
+ * //=> Mon Dec 01 2014 22:15:45.000
+ */
+export default function startOfSecond(dirtyDate) {
+  requiredArgs(1, arguments);
+  var date = toDate(dirtyDate);
+  date.setMilliseconds(0);
+  return date;
+}

node_modules/date-fns/esm/startOfSecond/index.js.flow

@@ -0,0 +1,52 @@
+// @flow
+// This file is generated automatically by `scripts/build/typings.js`. Please, don't change it.
+
+export type Interval = {
+  start: Date | number,
+  end: Date | number,
+}
+
+export type Locale = {
+  code?: string,
+  formatDistance?: (...args: Array<any>) => any,
+  formatRelative?: (...args: Array<any>) => any,
+  localize?: {
+    ordinalNumber: (...args: Array<any>) => any,
+    era: (...args: Array<any>) => any,
+    quarter: (...args: Array<any>) => any,
+    month: (...args: Array<any>) => any,
+    day: (...args: Array<any>) => any,
+    dayPeriod: (...args: Array<any>) => any,
+  },
+  formatLong?: {
+    date: (...args: Array<any>) => any,
+    time: (...args: Array<any>) => any,
+    dateTime: (...args: Array<any>) => any,
+  },
+  match?: {
+    ordinalNumber: (...args: Array<any>) => any,
+    era: (...args: Array<any>) => any,
+    quarter: (...args: Array<any>) => any,
+    month: (...args: Array<any>) => any,
+    day: (...args: Array<any>) => any,
+    dayPeriod: (...args: Array<any>) => any,
+  },
+  options?: {
+    weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6,
+    firstWeekContainsDate?: 1 | 2 | 3 | 4 | 5 | 6 | 7,
+  },
+}
+
+export type Duration = {
+  years?: number,
+  months?: number,
+  weeks?: number,
+  days?: number,
+  hours?: number,
+  minutes?: number,
+  seconds?: number,
+}
+
+export type Day = 0 | 1 | 2 | 3 | 4 | 5 | 6
+
+declare module.exports: (date: Date | number) => Date

node_modules/date-fns/esm/startOfSecond/package.json

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+{
+  "sideEffects": false,
+  "typings": "../../typings.d.ts"
+}