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/comment-parser/src/parser/spec-parser.ts

@@ -0,0 +1,20 @@
+import { Line, Spec } from '../primitives.js';
+import { seedSpec } from '../util.js';
+import { Tokenizer } from './tokenizers/index.js';
+
+export type Parser = (source: Line[]) => Spec;
+
+export interface Options {
+  tokenizers: Tokenizer[];
+}
+
+export default function getParser({ tokenizers }: Options): Parser {
+  return function parseSpec(source: Line[]): Spec {
+    let spec = seedSpec({ source });
+    for (const tokenize of tokenizers) {
+      spec = tokenize(spec);
+      if (spec.problems[spec.problems.length - 1]?.critical) break;
+    }
+    return spec;
+  };
+}