Feature request: Set user and/or password for the ISO

This would allow one to make headless installs, just insert usb, and ssh to the ip and sudo cachyos-installer to install via tui. As it is, if you lack a display, you need a keyboard and to manage to blindly set a password via cli.. not easy/hassle-free.
Cachyos for home servers is great :)

Start by tracing the ISO build configuration and the cachyos-installer entry point, focusing on how a headless USB boot currently handles user and password setup. Define the expected credential flow and verify that a user can boot without a display, connect over SSH, and run the installer through the TUI.

Written by the indexing model from the issue text.