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/fast-uri/.github/workflows/package-manager-ci.yml

@@ -0,0 +1,24 @@
+name: package-manager-ci
+
+on:
+  push:
+    branches:
+     - main
+     - next
+     - 'v*'
+    paths-ignore:
+      - 'docs/**'
+      - '*.md'
+  pull_request:
+    paths-ignore:
+      - 'docs/**'
+      - '*.md'
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    permissions:
+      contents: read
+    uses: fastify/workflows/.github/workflows/plugins-ci-package-manager.yml@v5