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/mdurl/CHANGELOG.md

@@ -0,0 +1,16 @@
+1.0.1 / 2015-09-15
+------------------
+
+- Fixed closure compiler compatibility (#1).
+
+
+1.0.0 / 2015-03-04
+------------------
+
+- Added `.decode()`, `.parse()`, `.format()`.
+
+
+0.0.1 / 2015-03-02
+------------------
+
+- First release.