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/buffer-crc32/package.json

@@ -0,0 +1,39 @@
+{
+  "author": "Brian J. Brennan <brianloveswords@gmail.com>",
+  "name": "buffer-crc32",
+  "description": "A pure javascript CRC32 algorithm that plays nice with binary data",
+  "version": "0.2.13",
+  "licenses": [
+    {
+      "type": "MIT",
+      "url": "https://github.com/brianloveswords/buffer-crc32/raw/master/LICENSE"
+    }
+  ],
+  "contributors": [
+    {
+      "name": "Vladimir Kuznetsov",
+      "github": "mistakster"
+    }
+  ],
+  "homepage": "https://github.com/brianloveswords/buffer-crc32",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/brianloveswords/buffer-crc32.git"
+  },
+  "main": "index.js",
+  "scripts": {
+    "test": "./node_modules/.bin/tap tests/*.test.js"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "tap": "~0.2.5"
+  },
+  "optionalDependencies": {},
+  "engines": {
+    "node": "*"
+  },
+  "license": "MIT",
+  "files": [
+    "index.js"
+  ]
+}