drop unused bench-create script + Makefile target

The script carried a python3 dep for one json.dumps on a VM name
that's always alphanumeric-plus-dashes anyway, it was never wired
into CI or docs, and `time banger vm create` covers the same need
ad hoc when anyone wants to measure create latency.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/bench-create.sh

@@ -1,120 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-log() {
-  printf '[bench-create] %s\n' "$*" >&2
-}
-
-usage() {
-  cat <<'EOF'
-Usage: ./scripts/bench-create.sh [--runs N] [--image NAME] [--keep]
-
-Measures:
-  - create_ms: time for `banger vm create`
-  - ssh_ready_ms: time until `banger vm ssh <vm> -- true` succeeds
-EOF
-}
-
-RUNS=5
-IMAGE_NAME=""
-KEEP=0
-
-while [[ $# -gt 0 ]]; do
-  case "$1" in
-    --runs)
-      RUNS="${2:-}"
-      shift 2
-      ;;
-    --image)
-      IMAGE_NAME="${2:-}"
-      shift 2
-      ;;
-    --keep)
-      KEEP=1
-      shift
-      ;;
-    -h|--help)
-      usage
-      exit 0
-      ;;
-    *)
-      log "unknown option: $1"
-      usage
-      exit 1
-      ;;
-  esac
-done
-
-if ! [[ "$RUNS" =~ ^[0-9]+$ ]] || [[ "$RUNS" -le 0 ]]; then
-  log "--runs must be a positive integer"
-  exit 1
-fi
-
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
-if [[ -z "${BANGER_BIN:-}" ]]; then
-  if [[ -x "$REPO_ROOT/build/bin/banger" ]]; then
-    BANGER_BIN="$REPO_ROOT/build/bin/banger"
-  else
-    BANGER_BIN="$REPO_ROOT/banger"
-  fi
-fi
-if [[ ! -x "$BANGER_BIN" ]]; then
-  log "banger binary not found: $BANGER_BIN"
-  log "run 'make build' or set BANGER_BIN"
-  exit 1
-fi
-
-timestamp_ms() {
-  date +%s%3N
-}
-
-json_escape() {
-  python3 - <<'PY' "$1"
-import json, sys
-print(json.dumps(sys.argv[1]))
-PY
-}
-
-printf '[\n'
-for run in $(seq 1 "$RUNS"); do
-  vm_name="bench-$(date +%s)-$run"
-  create_args=("$BANGER_BIN" vm create --name "$vm_name")
-  if [[ -n "$IMAGE_NAME" ]]; then
-    create_args+=(--image "$IMAGE_NAME")
-  fi
-
-  create_start="$(timestamp_ms)"
-  if ! "${create_args[@]}" >/dev/null; then
-    log "create failed for $vm_name"
-    exit 1
-  fi
-  create_end="$(timestamp_ms)"
-
-  ssh_start="$create_end"
-  ssh_ready=0
-  deadline=$((ssh_start + 60000))
-  while (( $(timestamp_ms) < deadline )); do
-    if "$BANGER_BIN" vm ssh "$vm_name" -- true >/dev/null 2>&1; then
-      ssh_ready="$(timestamp_ms)"
-      break
-    fi
-    sleep 0.5
-  done
-  if [[ "$ssh_ready" -eq 0 ]]; then
-    log "ssh did not become ready for $vm_name"
-    exit 1
-  fi
-
-  if [[ "$KEEP" -ne 1 ]]; then
-    "$BANGER_BIN" vm delete "$vm_name" >/dev/null || true
-  fi
-
-  printf '  {"run": %d, "vm_name": %s, "create_ms": %d, "ssh_ready_ms": %d}%s\n' \
-    "$run" \
-    "$(json_escape "$vm_name")" \
-    "$((create_end - create_start))" \
-    "$((ssh_ready - create_start))" \
-    "$( [[ "$run" -lt "$RUNS" ]] && printf ',' )"
-done
-printf ']\n'