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/@wordpress/components/build-module/animation/index.js

@@ -0,0 +1,11 @@
+/**
+ * Framer Motion is used to create animated, interactive interfaces. The package is roughly ~30kb so
+ * this should ideally be loaded once across all Gutenberg packages. To give ourselves more flexibility
+ * in trying animation options, we avoid making this public API.
+ *
+ * @see https://www.framer.com/docs/animation/
+ */
+
+// eslint-disable-next-line no-restricted-imports
+export { motion as __unstableMotion, AnimatePresence as __unstableAnimatePresence, MotionContext as __unstableMotionContext } from 'framer-motion';
+//# sourceMappingURL=index.js.map

node_modules/@wordpress/components/build-module/animation/index.js.map

@@ -0,0 +1 @@
+{"version":3,"names":["motion","__unstableMotion","AnimatePresence","__unstableAnimatePresence","MotionContext","__unstableMotionContext"],"sources":["@wordpress/components/src/animation/index.tsx"],"sourcesContent":["/**\n * Framer Motion is used to create animated, interactive interfaces. The package is roughly ~30kb so\n * this should ideally be loaded once across all Gutenberg packages. To give ourselves more flexibility\n * in trying animation options, we avoid making this public API.\n *\n * @see https://www.framer.com/docs/animation/\n */\n\n// eslint-disable-next-line no-restricted-imports\nexport {\n\tmotion as __unstableMotion,\n\tAnimatePresence as __unstableAnimatePresence,\n\tMotionContext as __unstableMotionContext,\n} from 'framer-motion';\n"],"mappings":"AAAA;AACA;AACA;AACA;AACA;AACA;AACA;;AAEA;AACA,SACCA,MAAM,IAAIC,gBAAgB,EAC1BC,eAAe,IAAIC,yBAAyB,EAC5CC,aAAa,IAAIC,uBAAuB,QAClC,eAAe"}