The URL parser previously required the hostname to contain "civitai.com", so CivitAI download links using the "civitai.red" domain were treated as non-CivitAI URLs and rejected. This extracts the host check into _is_civitai_host() and accepts both "civitai.com" and "civitai.red" base domains, so resolve/parse flows handle all CivitAI download links correctly.