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/rxjs/dist/esm5/internal/symbol/iterator.js

@@ -0,0 +1,8 @@
+export function getSymbolIterator() {
+    if (typeof Symbol !== 'function' || !Symbol.iterator) {
+        return '@@iterator';
+    }
+    return Symbol.iterator;
+}
+export var iterator = getSymbolIterator();
+//# sourceMappingURL=iterator.js.map

node_modules/rxjs/dist/esm5/internal/symbol/iterator.js.map

@@ -0,0 +1 @@
+{"version":3,"file":"iterator.js","sourceRoot":"","sources":["../../../../src/internal/symbol/iterator.ts"],"names":[],"mappings":"AAAA,MAAM,UAAU,iBAAiB;IAC/B,IAAI,OAAO,MAAM,KAAK,UAAU,IAAI,CAAC,MAAM,CAAC,QAAQ,EAAE;QACpD,OAAO,YAAmB,CAAC;KAC5B;IAED,OAAO,MAAM,CAAC,QAAQ,CAAC;AACzB,CAAC;AAED,MAAM,CAAC,IAAM,QAAQ,GAAG,iBAAiB,EAAE,CAAC"}

node_modules/rxjs/dist/esm5/internal/symbol/observable.js

@@ -0,0 +1,2 @@
+export var observable = (function () { return (typeof Symbol === 'function' && Symbol.observable) || '@@observable'; })();
+//# sourceMappingURL=observable.js.map

node_modules/rxjs/dist/esm5/internal/symbol/observable.js.map

@@ -0,0 +1 @@
+{"version":3,"file":"observable.js","sourceRoot":"","sources":["../../../../src/internal/symbol/observable.ts"],"names":[],"mappings":"AAMA,MAAM,CAAC,IAAM,UAAU,GAAoB,CAAC,cAAM,OAAA,CAAC,OAAO,MAAM,KAAK,UAAU,IAAI,MAAM,CAAC,UAAU,CAAC,IAAI,cAAc,EAArE,CAAqE,CAAC,EAAE,CAAC"}