Fix sleep lock session environment race (#6493)

Found by @tobi.

default/systemd/user/omarchy-sleep-lock.service

@@ -1,7 +1,13 @@
 [Unit]
 Description=Lock Omarchy before suspend
-After=dbus.socket
+# The monitor calls into the running Omarchy shell. Wait until UWSM has imported
+# OMARCHY_PATH and WAYLAND_DISPLAY, but keep the default target ordering so the
+# monitor starts before graphical-session.target is reached.
+After=dbus.socket wayland-session-waitenv.service
 Requires=dbus.socket
+PartOf=graphical-session.target
+ConditionEnvironment=OMARCHY_PATH
+ConditionEnvironment=WAYLAND_DISPLAY
 
 [Service]
 Type=simple