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/jpeg-js/index.d.ts

@@ -0,0 +1,36 @@
+export interface RawImageData<T> {
+  width: number;
+  height: number;
+  data: T;
+}
+
+type BufferRet = RawImageData<Buffer>;
+type UintArrRet = RawImageData<Uint8Array>;
+
+type ImageData = BufferRet | UintArrRet;
+type BufferLike = Buffer | Uint8Array | ArrayLike<number> | Iterable<number> | ArrayBuffer;
+
+export declare function encode(imgData: RawImageData<BufferLike> & {comments?: string[]}, quality?: number): BufferRet
+
+export declare function decode(
+  jpegData: BufferLike,
+  opts: {
+    useTArray: true;
+    colorTransform?: boolean;
+    formatAsRGBA?: boolean;
+    tolerantDecoding?: boolean;
+    maxResolutionInMP?: number;
+    maxMemoryUsageInMB?: number;
+  },
+): UintArrRet & {comments?: string[]};
+export declare function decode(
+  jpegData: BufferLike,
+  opts?: {
+    useTArray?: false;
+    colorTransform?: boolean;
+    formatAsRGBA?: boolean;
+    tolerantDecoding?: boolean;
+    maxResolutionInMP?: number;
+    maxMemoryUsageInMB?: number;
+  },
+): BufferRet & {comments?: string[]};