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/v8-compile-cache/README.md

@@ -0,0 +1,55 @@
+# v8-compile-cache
+
+[![Build Status](https://travis-ci.org/zertosh/v8-compile-cache.svg?branch=master)](https://travis-ci.org/zertosh/v8-compile-cache)
+
+`v8-compile-cache` attaches a `require` hook to use [V8's code cache](https://v8project.blogspot.com/2015/07/code-caching.html) to speed up instantiation time. The "code cache" is the work of parsing and compiling done by V8.
+
+The ability to tap into V8 to produce/consume this cache was introduced in [Node v5.7.0](https://nodejs.org/en/blog/release/v5.7.0/).
+
+## Usage
+
+1. Add the dependency:
+
+  ```sh
+  $ npm install --save v8-compile-cache
+  ```
+
+2. Then, in your entry module add:
+
+  ```js
+  require('v8-compile-cache');
+  ```
+
+**Requiring `v8-compile-cache` in Node <5.7.0 is a noop – but you need at least Node 4.0.0 to support the ES2015 syntax used by `v8-compile-cache`.**
+
+## Options
+
+Set the environment variable `DISABLE_V8_COMPILE_CACHE=1` to disable the cache.
+
+Cache directory is defined by environment variable `V8_COMPILE_CACHE_CACHE_DIR` or defaults to `<os.tmpdir()>/v8-compile-cache-<V8_VERSION>`.
+
+## Internals
+
+Cache files are suffixed `.BLOB` and `.MAP` corresponding to the entry module that required `v8-compile-cache`. The cache is _entry module specific_ because it is faster to load the entire code cache into memory at once, than it is to read it from disk on a file-by-file basis.
+
+## Benchmarks
+
+See https://github.com/zertosh/v8-compile-cache/tree/master/bench.
+
+**Load Times:**
+
+| Module           | Without Cache | With Cache |
+| ---------------- | -------------:| ----------:|
+| `babel-core`     | `218ms`       | `185ms`    |
+| `yarn`           | `153ms`       | `113ms`    |
+| `yarn` (bundled) | `228ms`       | `105ms`    |
+
+_^ Includes the overhead of loading the cache itself._
+
+## Acknowledgements
+
+* `FileSystemBlobStore` and `NativeCompileCache` are based on Atom's implementation of their v8 compile cache: 
+  - https://github.com/atom/atom/blob/b0d7a8a/src/file-system-blob-store.js
+  - https://github.com/atom/atom/blob/b0d7a8a/src/native-compile-cache.js
+* `mkdirpSync` is based on:
+  - https://github.com/substack/node-mkdirp/blob/f2003bb/index.js#L55-L98