Add pacman --overwrite for transition paths; fix mimeapps/HEY and PAM idempotency

Four corrections to the omarchy-settings transition:

- bin/omarchy-update-system-pkgs: pass --overwrite for the 13 paths
  omarchy-settings now owns. Existing Omarchy installs would otherwise
  fail pacman conflict checks on the upgrade that ships the package
  (the files exist as unowned filesystem entries from the previous
  install scripts). The flags are no-ops once the transition release
  is everyone's baseline; remove then.
- config/mimeapps.list: drop the HEY.desktop mailto mapping. HEY.desktop
  is generated by install/packaging/webapps.sh at install time, not
  shipped under applications/, so it isn't valid for a fresh /etc/skel
  user before the installer runs.
- install/config/mimetypes.sh: add 'xdg-mime default HEY.desktop
  x-scheme-handler/mailto' as a runtime op since the mapping no longer
  lives in mimeapps.list.
- install/config/increase-lockout-limit.sh: delete existing
  pam_faillock.so authsucc lines before re-adding, so re-running the
  installer doesn't duplicate the authsucc entry in
  /etc/pam.d/sddm-autologin.

bin/omarchy-update-system-pkgs

@@ -6,4 +6,26 @@
 set -e
 
 echo -e "\e[32m\nUpdate system packages\e[0m"
-sudo pacman -Syyu --noconfirm
+
+# Transition --overwrite: the Omarchy 4 package refactor moves files that
+# previous Omarchy installs wrote as unowned files (via install scripts) into
+# the omarchy-settings package. Pacman would otherwise refuse to install
+# omarchy-settings on the first upgrade because the paths "exist in
+# filesystem". Limited to the exact paths the package now owns; remove the
+# corresponding --overwrite entry once the transition release is everyone's
+# baseline.
+sudo pacman -Syyu --noconfirm \
+  --overwrite '/etc/docker/daemon.json' \
+  --overwrite '/etc/gnupg/dirmngr.conf' \
+  --overwrite '/etc/modprobe.d/omarchy-usb-autosuspend.conf' \
+  --overwrite '/etc/sudoers.d/omarchy-asdcontrol' \
+  --overwrite '/etc/sudoers.d/omarchy-passwd-tries' \
+  --overwrite '/etc/sudoers.d/omarchy-tzupdate' \
+  --overwrite '/etc/sysctl.d/90-omarchy-file-watchers.conf' \
+  --overwrite '/etc/sysctl.d/99-omarchy-sysctl.conf' \
+  --overwrite '/etc/systemd/logind.conf.d/10-ignore-power-button.conf' \
+  --overwrite '/etc/systemd/resolved.conf.d/10-disable-multicast.conf' \
+  --overwrite '/etc/systemd/resolved.conf.d/20-docker-dns.conf' \
+  --overwrite '/etc/systemd/system.conf.d/10-faster-shutdown.conf' \
+  --overwrite '/etc/systemd/system/user@.service.d/10-faster-shutdown.conf' \
+  --overwrite '/etc/systemd/system/docker.service.d/no-block-boot.conf'