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/debounce/package.json

@@ -0,0 +1,27 @@
+{
+  "name": "debounce",
+  "description": "Creates and returns a new debounced version of the passed function that will postpone its execution until after wait milliseconds have elapsed since the last time it was invoked",
+  "version": "1.2.1",
+  "repository": "git://github.com/component/debounce",
+  "main": "index.js",
+  "scripts": {
+    "test": "minijasminenode test.js"
+  },
+  "license": "MIT",
+  "keywords": [
+    "function",
+    "throttle",
+    "invoke"
+  ],
+  "devDependencies": {
+    "minijasminenode": "^1.1.1",
+    "sinon": "^1.17.7",
+    "mocha": "*",
+    "should": "*"
+  },
+  "component": {
+    "scripts": {
+      "debounce/index.js": "index.js"
+    }
+  }
+}