wip: save current ks debugging state before bisect revert

All accumulated changes to kickstart template, test infrastructure,
and dnsmasq config. None of these produce a clean boot yet — saving
state before reverting to baseline for bisection.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bastion/tests/integration/helpers/vm-screenshot.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# Capture a screenshot of a libvirt VM and convert to PNG for viewing.
+# Usage: vm-screenshot.sh [VM_NAME] [OUTPUT_PATH]
+VM_NAME="${1:-lab-pxe-test}"
+OUTPUT="${2:-/tmp/vm-screenshot.png}"
+PPM="/tmp/vm-screenshot-$$.ppm"
+
+if ! sudo virsh domstate "$VM_NAME" &>/dev/null; then
+    echo "ERROR: VM '$VM_NAME' not found or not running" >&2
+    exit 1
+fi
+
+sudo virsh screenshot "$VM_NAME" "$PPM" --screen 0 2>/dev/null
+if [ ! -f "$PPM" ]; then
+    echo "ERROR: screenshot failed" >&2
+    exit 1
+fi
+
+# Convert to PNG (ppm -> png)
+if command -v convert &>/dev/null; then
+    convert "$PPM" "$OUTPUT"
+elif command -v ffmpeg &>/dev/null; then
+    ffmpeg -y -i "$PPM" "$OUTPUT" 2>/dev/null
+elif command -v pnmtopng &>/dev/null; then
+    pnmtopng "$PPM" > "$OUTPUT"
+else
+    # fallback: just copy the PPM (Read tool can handle it)
+    cp "$PPM" "${OUTPUT%.png}.ppm"
+    OUTPUT="${OUTPUT%.png}.ppm"
+fi
+
+rm -f "$PPM"
+echo "$OUTPUT"