refactor(mpv): move ModernZ overrides into mpv.conf via script-opts-append

- drop defaults/etc/mpv/script-opts/modernz.conf (deploy timing conflict
  with mpv-modernz-git)
- put all ModernZ tweaks in mpv.conf: Catppuccin Lavender accent, scale
  0.75, title font 18, ontop_button off, autofit-larger 80%
- quote hex values to survive mpv's mid-line # comment parsing
- niri window-rule opens mpv floating
- doctor no longer compares mpv configs (now directly owned by pkg)

scripts/moonarch-doctor

@@ -199,8 +199,6 @@ check_config_match "/etc/xdg/swaync/style.css"      "$SRC/swaync/style.css"
 check_config_match "/etc/greetd/config.toml"         "$SRC/greetd/config.toml"
 check_config_match "/etc/greetd/niri-greeter.kdl"    "$SRC/greetd/niri-greeter.kdl"
 check_config_match "/etc/moongreet/moongreet.toml"   "$SRC/moongreet/moongreet.toml"
-check_config_match "/etc/mpv/mpv.conf"               "$SRC/mpv/mpv.conf"
-check_config_match "/etc/mpv/script-opts/modernz.conf" "$SRC/mpv/modernz.conf"
 
 if [[ -f /etc/zsh/zshrc.moonarch ]]; then
     pass "/etc/zsh/zshrc.moonarch"