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/@tootallnate/quickjs-emscripten/dist/memory.d.ts

@@ -0,0 +1,18 @@
+import { EitherModule } from "./emscripten-types";
+import { OwnedHeapCharPointer, JSContextPointerPointer, JSValueConstPointerPointer, JSValuePointerPointer } from "./types-ffi";
+import { Lifetime } from "./lifetime";
+import { QuickJSHandle } from "./types";
+/**
+ * @private
+ */
+export declare class ModuleMemory {
+    module: EitherModule;
+    constructor(module: EitherModule);
+    toPointerArray(handleArray: QuickJSHandle[]): Lifetime<JSValueConstPointerPointer>;
+    newMutablePointerArray<T extends JSContextPointerPointer | JSValuePointerPointer>(length: number): Lifetime<{
+        typedArray: Int32Array;
+        ptr: T;
+    }>;
+    newHeapCharPointer(string: string): Lifetime<OwnedHeapCharPointer>;
+    consumeHeapCharPointer(ptr: OwnedHeapCharPointer): string;
+}