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/ajv/lib/dot/oneOf.jst

@@ -0,0 +1,54 @@
+{{# def.definitions }}
+{{# def.errors }}
+{{# def.setupKeyword }}
+{{# def.setupNextLevel }}
+
+{{
+  var $currentBaseId = $it.baseId
+    , $prevValid = 'prevValid' + $lvl
+    , $passingSchemas = 'passingSchemas' + $lvl;
+}}
+
+var {{=$errs}} = errors
+  , {{=$prevValid}} = false
+  , {{=$valid}} = false
+  , {{=$passingSchemas}} = null;
+
+{{# def.setCompositeRule }}
+
+{{~ $schema:$sch:$i }}
+  {{? {{# def.nonEmptySchema:$sch }} }}
+    {{
+      $it.schema = $sch;
+      $it.schemaPath = $schemaPath + '[' + $i + ']';
+      $it.errSchemaPath = $errSchemaPath + '/' + $i;
+    }}
+
+    {{# def.insertSubschemaCode }}
+  {{??}}
+    var {{=$nextValid}} = true;
+  {{?}}
+
+  {{? $i }}
+    if ({{=$nextValid}} && {{=$prevValid}}) {
+      {{=$valid}} = false;
+      {{=$passingSchemas}} = [{{=$passingSchemas}}, {{=$i}}];
+    } else {
+    {{ $closingBraces += '}'; }}
+  {{?}}
+
+    if ({{=$nextValid}}) {
+      {{=$valid}} = {{=$prevValid}} = true;
+      {{=$passingSchemas}} = {{=$i}};
+    }
+{{~}}
+
+{{# def.resetCompositeRule }}
+
+{{= $closingBraces }}
+
+if (!{{=$valid}}) {
+  {{# def.extraError:'oneOf' }}
+} else {
+  {{# def.resetErrors }}
+{{? it.opts.allErrors }} } {{?}}