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/launch-editor/index.d.ts

@@ -0,0 +1,16 @@
+/**
+ * Launch an editor to open a file at a specific line and column.
+ *
+ * @param file File path with optional line and column numbers (e.g.
+ *   "/path/to/file.js:10:2").
+ * @param specifiedEditor Optional editor command or path to use. Will be
+ *   parsed using `shell-quote`.
+ * @param onErrorCallback Optional callback for handling errors.
+ */
+declare function launchEditor(
+  file: string,
+  specifiedEditor?: string | ((fileName: string, errorMessage: string | null) => void),
+  onErrorCallback?: (fileName: string, errorMessage: string | null) => void
+): void;
+
+export = launchEditor;