Fires after the channel template is copied to /etc/pacman.conf and before
`pacman -Syyuu` runs, letting users layer custom Pacman repositories or
IgnorePkg directives onto the freshly-written config so they're respected
by the upgrade. Useful for users running on overlay distros (CachyOS,
Chaotic-AUR, internal company repos) where a wipe-and-reinstall would
otherwise pull vanilla Arch versions.
Ships with `pre-refresh-pacman.d/add-custom-repo.sample` showing the
pattern.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>