Plus FluentCart Shop Slug Fix

The Shop Slug Fix is an opt-in Storefront Tweaks workaround in Plus for FluentCart. It handles the case where the configured shop-page path is identical to FluentCart's product slug, causing WordPress to resolve the exact shop URL as the product archive instead of the assigned page.

The implementation checks the exact assigned shop path and rewrites that request to the page ID. Child product URLs under the same slug are left alone, and the documented code does not require flushing rewrite rules. Enable it for the specific collision rather than treating it as a general permalink repair tool.