Remember power profile choices per power source across reboots

Explicit profile selections from the power panel or menu are now saved
under an ac/battery key in ~/.local/state/omarchy/powerprofiles and
reapplied on boot and on plug/unplug. Only successful, user-made
selections are persisted, so the performance/balanced defaults still
apply when nothing has been chosen.

All entry points key off the same power signal, UPower's OnBattery:
the shell reads it natively and omarchy-powerprofiles-set autodetect
queries it via busctl. This replaces the sysfs online checks, which
disagreed with the shell on desktops without power_supply entries and
lagged behind plug events on some USB-C laptops.

Plug/unplug switching moves from the udev rule into the shell's battery
service, which already receives UPower's debounced state changes, so
the udev rule and its settle-sleep workaround are gone.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

shell/plugins/panels/power/Panel.qml

@@ -157,7 +157,7 @@ Panel {
 
   function setProfile(profile) {
     if (!profile || actionProc.running) return
-    actionProc.command = ["powerprofilesctl", "set", profile]
+    actionProc.command = ["omarchy-powerprofiles-set", root.discharging ? "battery" : "ac", profile]
     actionProc.running = true
   }