Improve VM lifecycle tooling

Make spawned VMs easier to use and restore from the host.

Add shared DNS and runtime helpers, publish <vm-name>.vm records through mapdns, and teach run/customize/interactive/restore to persist the metadata needed for SSH, DNS cleanup, and clean restores.

Seed per-VM /home and /var disks from the rootfs snapshot so package state is present on first boot, add an interactive customization entrypoint plus ssh.sh and human-friendly list output, and let stop/kill/rm operate on multiple VM identifiers.

Tear down stale TAP, dm, and loop state when VMs stop so restore can recreate them safely, and validate the updated scripts with bash -n plus targeted dry-run harnesses for teardown and restore paths.

stop.sh

@@ -5,9 +5,14 @@ log() {
   printf '[stop] %s\n' "$*"
 }
 
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$DIR/dns.sh"
+STATE="$DIR/state"
+VM_ROOT="$STATE/vms"
+
 usage() {
   cat <<'EOF'
-Usage: ./stop.sh <id-or-name-prefix>
+Usage: ./stop.sh <id-or-name-prefix>...
 
 Sends Ctrl+Alt+Del to the guest via the Firecracker API socket.
 EOF
@@ -17,7 +22,7 @@ find_vm_json() {
   local query="$1"
   local vm_json match_count=0 match=""
 
-  for vm_json in state/vms/*/vm.json; do
+  for vm_json in "$VM_ROOT"/*/vm.json; do
     [[ -f "$vm_json" ]] || continue
     local id name
     id="$(jq -r '.meta.id // empty' "$vm_json")"
@@ -40,21 +45,64 @@ find_vm_json() {
   printf '%s' "$match"
 }
 
-QUERY="${1:-}"
-if [[ -z "$QUERY" || "$QUERY" == "-h" || "$QUERY" == "--help" ]]; then
+QUERIES=("$@")
+if (( ${#QUERIES[@]} == 1 )) && [[ "${QUERIES[0]}" == "-h" || "${QUERIES[0]}" == "--help" ]]; then
+  usage
+  exit 0
+fi
+if (( ${#QUERIES[@]} == 0 )); then
   usage
   exit 1
 fi
 
-VM_JSON="$(find_vm_json "$QUERY")"
-API_SOCK="$(jq -r '.meta.api_sock // empty' "$VM_JSON")"
-if [[ -z "$API_SOCK" || ! -S "$API_SOCK" ]]; then
-  log "api socket not found: $API_SOCK"
-  exit 1
-fi
+VM_JSONS=()
+for query in "${QUERIES[@]}"; do
+  VM_JSON="$(find_vm_json "$query")"
+  already_added=0
+  for existing_vm_json in "${VM_JSONS[@]}"; do
+    if [[ "$existing_vm_json" == "$VM_JSON" ]]; then
+      already_added=1
+      break
+    fi
+  done
+  if (( already_added == 0 )); then
+    VM_JSONS+=("$VM_JSON")
+  fi
+done
 
-log "sending Ctrl+Alt+Del to guest"
-sudo -E curl --unix-socket "$API_SOCK" -X PUT http://localhost/actions \
-  -H "Content-Type: application/json" \
-  -d '{ "action_type": "SendCtrlAltDel" }' >/dev/null
-log "requested shutdown"
+for vm_json in "${VM_JSONS[@]}"; do
+  vm_id="$(jq -r '.meta.id // empty' "$vm_json")"
+  vm_name="$(jq -r '.meta.name // empty' "$vm_json")"
+  pid="$(jq -r '.meta.pid // empty' "$vm_json")"
+  tap="$(jq -r '.meta.tap // empty' "$vm_json")"
+  api_sock="$(jq -r '.meta.api_sock // empty' "$vm_json")"
+  base_loop="$(jq -r '.meta.base_loop // empty' "$vm_json")"
+  cow_loop="$(jq -r '.meta.cow_loop // empty' "$vm_json")"
+  dm_dev="$(jq -r '.meta.dm_dev // empty' "$vm_json")"
+  dm_name="$(jq -r '.meta.dm_name // empty' "$vm_json")"
+  dns_name="$(jq -r '.meta.dns_name // empty' "$vm_json")"
+  if [[ -z "$dns_name" ]]; then
+    dns_name="$(banger_dns_name "$vm_name")"
+  fi
+  if [[ -z "$pid" ]]; then
+    log "pid not found for ${vm_name:-$vm_json}"
+    exit 1
+  fi
+  if [[ -z "$api_sock" || ! -S "$api_sock" ]]; then
+    log "api socket not found for ${vm_name:-$vm_json}: $api_sock"
+    exit 1
+  fi
+
+  log "sending Ctrl+Alt+Del to ${vm_name:-$vm_json}"
+  sudo -E curl --unix-socket "$api_sock" -X PUT http://localhost/actions \
+    -H "Content-Type: application/json" \
+    -d '{ "action_type": "SendCtrlAltDel" }' >/dev/null
+  if ! banger_wait_for_vm_exit "$pid" "$api_sock" 30; then
+    log "timed out waiting for ${vm_name:-$vm_json} to exit"
+    exit 1
+  fi
+  banger_teardown_vm_runtime "$tap" "$api_sock" "$dm_name" "$dm_dev" "$cow_loop" "$base_loop"
+  banger_mark_vm_stopped "$vm_json"
+  banger_dns_remove_record_name "$dns_name"
+  log "requested shutdown for ${vm_name:-$vm_json}"
+done