Migrate to linux-omarchy except on T2 Macs (#11845)

Backport of #11845 for v4-0-4. Supersedes #11729 with the final generic
kernel migration, without introducing the intermediate PTL migration.

Resolve against 4.0.3: remove the retired PTL installer, update the ISO
package list and NVIDIA headers, and retain the release hardware scope.
Cam Link and Dell sidecar support are absent from this release branch,
so omit their installer and test changes.

(cherry picked from commit 86a2e5830e)

install/hardware/intel/ptl-kernel.sh

@@ -1,25 +0,0 @@
-# Install Panther Lake kernel for Dell XPS Panther Lake systems
-# The linux-ptl kernel includes audio driver patches not yet in mainline.
-
-if omarchy-hw-match "XPS" && omarchy-hw-intel-ptl; then
-  echo "Detected Dell XPS Panther Lake, installing PTL kernel..."
-
-  omarchy-pkg-add linux-ptl linux-ptl-headers
-  pacman -Rdd --noconfirm linux linux-headers || true
-
-  # linux-ptl doesn't provide=linux, so anything depending on linux drags the
-  # stock kernel back in and the boot menu grows a second, slower entry.
-  if pacman -Qq linux &>/dev/null; then
-    echo "WARNING: stock linux kernel still installed alongside linux-ptl:"
-    pacman -Qi linux | grep -i "required by"
-  fi
-
-  mkdir -p /etc/limine-entry-tool.d
-  # Named to sort after omarchy-defaults.conf: drop-ins are read in order and
-  # the last BOOT_ORDER wins, so an earlier-sorting name is a silent no-op.
-  rm -f /etc/limine-entry-tool.d/dell-xps-panther-lake.conf
-  cat > /etc/limine-entry-tool.d/zz-dell-xps-panther-lake.conf <<'EOF'
-# Only show Panther Lake kernel in boot menu on Dell XPS Panther Lake
-BOOT_ORDER="linux-ptl*, *fallback, Snapshots"
-EOF
-fi