Ship zram tuning as a vendor drop-in

pacman checks file conflicts during transaction prepare, so the --overwrite
entry added alongside /etc/systemd/zram-generator.conf never got to run: the
copy of omarchy-update-system-pkgs driving the upgrade is the one already on
disk. Every machine carrying archinstall's copy aborted the transaction.

zram-generator.conf(5) reserves /etc for the local admin and has vendors ship
snippets under /usr/lib/systemd/zram-generator.conf.d/, where drop-ins outrank
the main config file. Nothing collides, and the tuning wins whether or not
archinstall's file is still around.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LjeyQZsNBxqyYy9z8KaKm7

test/shell.d/config-test.sh

@@ -122,6 +122,7 @@ package_defaults = [
   ("default/systemd/user/omarchy-recover-internal-monitor.service", "/usr/lib/systemd/user/omarchy-recover-internal-monitor.service", "systemd/user/omarchy-recover-internal-monitor.service"),
   ("default/systemd/user/omarchy-update-user-notify.service", "/usr/lib/systemd/user/omarchy-update-user-notify.service", "systemd/user/omarchy-update-user-notify.service"),
   ("default/systemd/user/omarchy-update-user-notify.path", "/usr/lib/systemd/user/omarchy-update-user-notify.path", "systemd/user/omarchy-update-user-notify.path"),
+  ("default/systemd/zram-generator.conf.d/90-omarchy.conf", "/usr/lib/systemd/zram-generator.conf.d/90-omarchy.conf", "systemd/zram-generator.conf.d/90-omarchy.conf"),
   ("default/fonts/omarchy/omarchy.ttf", "/usr/share/fonts/omarchy/omarchy.ttf", "omarchy.ttf"),
   ("default/snapper/root", "/etc/snapper/config-templates/omarchy", "snapper/root"),
 ]