The lua-based monitors config (~/.config/hypr/monitors.lua) ships from
skel with sensible defaults (omarchy_gdk_scale = 2, omarchy_monitor_scale
= "auto"). Hyprland handles the dynamic monitor scale at runtime via
"auto"; 'omarchy hyprland monitor scaling <N>' already updates both
omarchy_monitor_scale and omarchy_gdk_scale in monitors.lua when the
user wants to adjust.
The first-run 'detect what hyprland picked and write it back' dance
was leftover from the .conf-based config; it's redundant on the lua
flow and was the script that aborted omarchy-first-run under set -e
when it sed'd a missing monitors.conf.