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/lodash/_baseInRange.js

@@ -0,0 +1,18 @@
+/* Built-in method references for those with the same name as other `lodash` methods. */
+var nativeMax = Math.max,
+    nativeMin = Math.min;
+
+/**
+ * The base implementation of `_.inRange` which doesn't coerce arguments.
+ *
+ * @private
+ * @param {number} number The number to check.
+ * @param {number} start The start of the range.
+ * @param {number} end The end of the range.
+ * @returns {boolean} Returns `true` if `number` is in the range, else `false`.
+ */
+function baseInRange(number, start, end) {
+  return number >= nativeMin(start, end) && number < nativeMax(start, end);
+}
+
+module.exports = baseInRange;