Call to undefined method Category::getCartProductShowPid() — missing Extbase Object substitution

[Hobokens]

Bug Report

Current Behavior
Rendering a cartproducts_listproducts (or cartproducts_showproduct) plugin whose product has a category throws a fatal error:

Call to undefined method TYPO3\CMS\Extbase\Domain\Model\Category::getCartProductShowPid()
in Classes/ViewHelpers/Link/ProductViewHelper.php line 102

Expected behavior/output
The extended Extcode\CartProducts\Domain\Model\Category (which provides getCartProductShowPid() / getCartProductListPid()) should be used wherever a category is loaded via a product, so the plugin renders without error.

Environment

• TYPO3 version(s): 14.3
• cart-products version: dev-main (8.x branch)
• Is your TYPO3 installation set up with Composer (Composer Mode): yes
• OS: Windows 11 (via ddev/Docker)

Possible Solution
Configuration/Extbase/Persistence/Classes.php maps Extcode\CartProducts\Domain\Model\Category to the sys_category table, but that only configures persistence (table mapping) — it does not register an Extbase Object substitution. extcode/cart's CategoryTrait::getCategory() is typed to the core TYPO3\CMS\Extbase\Domain\Model\Category, so without a substitution Extbase hydrates the plain core class instead of the extended one.

Adding the following to ext_localconf.php resolves the issue:

$GLOBALS['TYPO3_CONF_VARS']['SYS']['Objects'][\TYPO3\CMS\Extbase\Domain\Model\Category::class] = [
    'className' => \Extcode\CartProducts\Domain\Model\Category::class,
];

Additional context
Confirmed by registering the substitution manually in a site extension's ext_localconf.php — the error disappears immediately.