fix(ci): isolate agent smoke in namespace-capable helper

scripts/ci/linux-agent-container-smoke.test.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env sh
+# Exercise the wrapper without a Docker daemon or any firewall operation.
+set -eu
+wrapper="$(pwd)/scripts/ci/linux-agent-container-smoke.sh"
+tmp="$(mktemp -d)"
+trap 'rm -rf "$tmp"' EXIT HUP INT TERM
+mkdir "$tmp/bin"
+cat >"$tmp/bin/docker" <<'DOCKER'
+#!/usr/bin/env sh
+set -eu
+printf '%s\n' "$*" >>"$FAKE_LOG"
+case "$1" in
+  info)
+    case "$*" in
+      *SecurityOptions*) if [ "$FAKE_APPARMOR" = true ]; then printf '["name=apparmor","name=seccomp,profile=default"]\n'; else printf '["name=seccomp,profile=default"]\n'; fi ;;
+      *) printf 'linux\n' ;;
+    esac ;;
+  build)
+    while [ "$#" -gt 0 ]; do
+      if [ "$1" = --iidfile ]; then shift; printf 'sha256:%064d\n' 0 >"$1"; break; fi
+      shift
+    done ;;
+  run) exit "$FAKE_RUN_EXIT" ;;
+  rm|image) exit 0 ;;
+  *) exit 98 ;;
+esac
+DOCKER
+chmod +x "$tmp/bin/docker"
+for expected in 0 23; do
+  log="$tmp/docker-$expected.log"
+  apparmor=false; [ "$expected" = 0 ] || apparmor=true
+  if PATH="$tmp/bin:$PATH" FAKE_LOG="$log" FAKE_APPARMOR="$apparmor" FAKE_RUN_EXIT="$expected" sh "$wrapper"; then actual=0; else actual=$?; fi
+  [ "$actual" = "$expected" ] || { echo 'Wrapper did not preserve the container exit code' >&2; exit 1; }
+  grep -F 'build --file scripts/ci/linux-agent-smoke.Dockerfile --iidfile ' "$log" >/dev/null
+  grep -F ' --network none --cap-drop ALL --cap-add SYS_ADMIN --cap-add NET_ADMIN ' "$log" >/dev/null
+  grep -F ' --security-opt no-new-privileges:true --read-only --tmpfs /tmp:' "$log" >/dev/null
+  grep -F 'image rm sha256:' "$log" >/dev/null
+  grep -E '^rm -f evofw-linux-smoke-' "$log" >/dev/null
+  if grep -E -- '(--privileged|--network host|--pid host|--mount|--volume|docker.sock|seccomp=)' "$log" >/dev/null; then echo 'Unsafe helper isolation flags' >&2; exit 1; fi
+  if [ "$apparmor" = true ]; then grep -F ' --security-opt apparmor=unconfined ' "$log" >/dev/null
+  elif grep -F 'apparmor=unconfined' "$log" >/dev/null; then echo 'Unneeded AppArmor exception' >&2; exit 1
+  fi
+done
+echo 'Helper wrapper regression passed (flags, remote context, exit status, cleanup)'