GHSA-p9xj-fpr2-jf2q

### Description The `ux:install` console command installs files from a recipe kit by copying paths listed in a `copy-files` map. The only guard against malicious paths was `Path::isRelative()`, which returns `true` for paths like `../../../etc`. `Path::join()` then resolves the `..` segments without complaint, so the final path can escape the intended directory entirely. A crafted or compromised kit can therefore write attacker-controlled content to arbitrary locations on the developer's machine or CI runner.

Because the copy operation creates missing parent directories and can overwrite existing files silently (with `--force` or in non-interactive environments), an attacker who controls a kit can overwrite files such as controllers, git hooks, or `.env` to achieve code execution. The source side of `copy-files` is symmetrically affected, enabling local file reads outside the recipe directory.

### Resolution

The fix introduces an `Assert::pathDoesNotEscapeDirectory()` helper that rejects any `copy-files` source or destination path containing a `..` segment, regardless of whether `/` or `\` is used as the separator. This check is enforced in both `RecipeManifest` (which also guards the source Finder) and `File`. As a last line of defense, the installer re-verifies the fully resolved paths with `Path::isBasePath()` immediately before each filesystem read and write.

### Credits

Symfony would like to thank Pascal Cescon for reporting the issue and Hugo Alliaume for providing the fix.