Move speaker reboot bookkeeping into the migration

Keep hardware setup limited to installing the firmware package. The migration owns the pending-reboot marker and preserves prompts for every user migrating before reboot.

migrations/1791265613.sh

@@ -1,10 +1,14 @@
 echo "Install the Dell XPS 13 Panther Lake speaker firmware"
 
 if omarchy-hw-dell-xps13-dx13260-ptl; then
+  firmware_pending="/run/omarchy/xps13-ptl-speaker-firmware"
+  if omarchy-pkg-missing linux-firmware-cirrus-dx13260; then
+    sudo install -Dm644 /dev/null "$firmware_pending"
+  fi
+
   source "$OMARCHY_PATH/install/hardware/dell-xps13-ptl-speaker-firmware.sh"
 
   # The marker lasts until reboot so every user migrating beforehand is prompted.
-  firmware_pending="/run/omarchy/xps13-ptl-speaker-firmware"
   if [[ -e $firmware_pending ]]; then
     omarchy-state set reboot-required
   fi