Make setup ISO-only

Remove legacy online installer entrypoints, collapse migrations for 4.0, and move setup responsibilities into target-side system, hardware, and user commands.

install/hardware/intel/ptl-kernel.sh

@@ -0,0 +1,15 @@
+# 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 2>/dev/null || true
+
+  mkdir -p /etc/limine-entry-tool.d
+  cat > /etc/limine-entry-tool.d/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