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/normalize-package-data/lib/make_warning.js

@@ -0,0 +1,22 @@
+var util = require('util')
+var messages = require('./warning_messages.json')
+
+module.exports = function () {
+  var args = Array.prototype.slice.call(arguments, 0)
+  var warningName = args.shift()
+  if (warningName === 'typo') {
+    return makeTypoWarning.apply(null, args)
+  } else {
+    var msgTemplate = messages[warningName] ? messages[warningName] : warningName + ": '%s'"
+    args.unshift(msgTemplate)
+    return util.format.apply(null, args)
+  }
+}
+
+function makeTypoWarning (providedName, probableName, field) {
+  if (field) {
+    providedName = field + "['" + providedName + "']"
+    probableName = field + "['" + probableName + "']"
+  }
+  return util.format(messages.typo, providedName, probableName)
+}