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/escape-html/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "escape-html",
+  "description": "Escape string for use in HTML",
+  "version": "1.0.3",
+  "license": "MIT",
+  "keywords": [
+    "escape",
+    "html",
+    "utility"
+  ],
+  "repository": "component/escape-html",
+  "devDependencies": {
+    "benchmark": "1.0.0",
+    "beautify-benchmark": "0.2.4"
+  },
+  "files": [
+    "LICENSE",
+    "Readme.md",
+    "index.js"
+  ],
+  "scripts": {
+    "bench": "node benchmark/index.js"
+  }
+}