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/mousetrap/plugins/pause/README.md

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+# Pause/unpause
+
+This extension allows Mousetrap to be paused and unpaused without having to reset keyboard shortcuts and rebind them.
+
+Usage looks like:
+
+```javascript
+// stop Mousetrap events from firing
+Mousetrap.pause();
+
+// allow Mousetrap events to fire again
+Mousetrap.unpause();
+```

node_modules/mousetrap/plugins/pause/mousetrap-pause.js

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+/**
+ * adds a pause and unpause method to Mousetrap
+ * this allows you to enable or disable keyboard shortcuts
+ * without having to reset Mousetrap and rebind everything
+ */
+/* global Mousetrap:true */
+(function(Mousetrap) {
+    var _originalStopCallback = Mousetrap.prototype.stopCallback;
+
+    Mousetrap.prototype.stopCallback = function(e, element, combo) {
+        var self = this;
+
+        if (self.paused) {
+            return true;
+        }
+
+        return _originalStopCallback.call(self, e, element, combo);
+    };
+
+    Mousetrap.prototype.pause = function() {
+        var self = this;
+        self.paused = true;
+    };
+
+    Mousetrap.prototype.unpause = function() {
+        var self = this;
+        self.paused = false;
+    };
+
+    Mousetrap.init();
+}) (Mousetrap);

node_modules/mousetrap/plugins/pause/mousetrap-pause.min.js

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+(function(a){var b=a.prototype.stopCallback;a.prototype.stopCallback=function(a,c,d){return this.paused?!0:b.call(this,a,c,d)};a.prototype.pause=function(){this.paused=!0};a.prototype.unpause=function(){this.paused=!1};a.init()})(Mousetrap);