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/@emotion/react/dist/declarations/src/index.d.ts

@@ -0,0 +1,14 @@
+export type { EmotionCache } from '@emotion/cache';
+export type { ArrayInterpolation, ComponentSelector, CSSObject, FunctionInterpolation, Interpolation, Keyframes, SerializedStyles } from '@emotion/serialize';
+export { withEmotionCache, CacheProvider, __unsafe_useEmotionCache } from "./context.js";
+export { jsx } from "./jsx.js";
+export { jsx as createElement } from "./jsx.js";
+export { Global } from "./global.js";
+export type { GlobalProps } from "./global.js";
+export { keyframes } from "./keyframes.js";
+export { ClassNames } from "./class-names.js";
+export type { ClassNamesArg, ClassNamesContent, ClassNamesProps, ArrayClassNamesArg } from "./class-names.js";
+export { ThemeContext, useTheme, ThemeProvider, withTheme } from "./theming.js";
+export type { Theme, ThemeProviderProps, WithTheme } from "./theming.js";
+export { default as css } from "./css.js";
+export type { DistributiveOmit, PropsOf } from "./types.js";