ci: add GitLab CI pipeline and rootfs smoke tests

- tests/: offline tree validation plus rootfs smoke tests that assert
  the hardening guarantees (kptr_restrict, default-deny firewall,
  key-only ssh, no snapd/telemetry, btrfs tooling).
- ci/: GitLab pipeline - validate, build matrix (server/workstation/
  cloud), smoke tests, publish on tags.

tests/run-tests.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# ─────────────────────────────────────────────────────────────────────────────
+# Arcline OS — test runner
+#
+#   tests/run-tests.sh                    # validate tree + test built rootfs(s)
+#   tests/run-tests.sh server             # test a specific edition
+#
+# Verifies:
+#   1. the whole build tree is syntactically valid (validate.sh)
+#   2. any built rootfs in build/rootfs/<edition> satisfies the hardening
+#      and packaging guarantees (tests/smoke/verify-rootfs.sh)
+# ─────────────────────────────────────────────────────────────────────────────
+set -euo pipefail
+source "$(dirname "${BASH_SOURCE[0]}")/../scripts/common.sh"
+
+fail=0
+
+log "step 1/2 — tree validation"
+"$ROOT/scripts/validate.sh" || fail=1
+
+log "step 2/2 — rootfs smoke tests"
+editions=("${EDITIONS[@]}")
+[[ $# -gt 0 ]] && editions=("$@")
+
+for e in "${editions[@]}"; do
+  rootfs="$ROOTFS_DIR/$e"
+  if [[ ! -d "$rootfs" ]]; then
+    warn "no rootfs for '$e' at $rootfs — skipping smoke test"
+    continue
+  fi
+  log "smoke testing rootfs: $e"
+  if ! "$ROOT/tests/smoke/verify-rootfs.sh" "$rootfs"; then
+    warn "smoke test failed for '$e'"
+    fail=1
+  fi
+done
+
+if [[ $fail -eq 0 ]]; then
+  log "tests passed ✓"
+else
+  die "tests failed"
+fi

tests/smoke/verify-rootfs.sh

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+# ─────────────────────────────────────────────────────────────────────────────
+# Arcline OS — rootfs smoke test
+#
+#   tests/smoke/verify-rootfs.sh <rootfs>
+#
+# Asserts the packaging + hardening guarantees of a built rootfs. Runs
+# read-only against an extracted rootfs tree (no chroot needed). A failed
+# assertion exits nonzero with a message.
+# ─────────────────────────────────────────────────────────────────────────────
+set -euo pipefail
+
+ROOTFS="${1:?usage: verify-rootfs.sh <rootfs>}"
+[[ -d "$ROOTFS" ]] || { echo "FAIL: rootfs not found: $ROOTFS"; exit 1; }
+
+pass=0; fail=0
+ok()   { printf '  \033[32m✓\033[0m %s\n' "$*"; pass=$((pass+1)); }
+bad()  { printf '  \033[31m✗\033[0m %s\n' "$*"; fail=$((fail+1)); }
+
+have_file() { [[ -f "$ROOTFS/$1" ]]; }
+have_dir()  { [[ -d "$ROOTFS/$1" ]]; }
+
+echo "─ hardening ───────────────────────────────────────────"
+if have_file "etc/sysctl.d/10-arcline-hardening.conf"; then
+  grep -q 'kernel.kptr_restrict=2' "$ROOTFS/etc/sysctl.d/10-arcline-hardening.conf" \
+    && ok "sysctl hardening present (kptr_restrict=2)" || bad "sysctl file missing kptr_restrict=2"
+else
+  bad "missing etc/sysctl.d/10-arcline-hardening.conf"
+fi
+
+if have_file "etc/nftables.conf"; then
+  grep -q 'policy drop' "$ROOTFS/etc/nftables.conf" \
+    && ok "nftables default-deny present" || bad "nftables policy is not drop"
+else
+  bad "missing etc/nftables.conf"
+fi
+
+if have_file "etc/ssh/sshd_config.d/10-arcline-hardening.conf"; then
+  grep -q 'PasswordAuthentication no' "$ROOTFS/etc/ssh/sshd_config.d/10-arcline-hardening.conf" \
+    && ok "ssh hardening present" || bad "ssh password auth not disabled"
+else
+  bad "missing ssh hardening drop-in"
+fi
+
+have_file "etc/systemd/journald.conf.d/10-arcline.conf" \
+  && ok "journald persistent config present" || bad "missing journald config"
+have_file "etc/modprobe.d/arcline-hardening.conf" \
+  && ok "module blacklist present" || bad "missing modprobe blacklist"
+
+echo "─ telemetry (must be absent) ──────────────────────────"
+if have_dir "var/lib/ubuntu-report" || have_dir "var/lib/popularity-contest"; then
+  bad "telemetry package artifacts found (ubuntu-report / popularity-contest)"
+else
+  ok "no distro telemetry artifacts"
+fi
+if [[ -d "$ROOTFS/usr/lib/snapd" ]]; then
+  bad "snapd found (Arcline is snap-free)"
+else
+  ok "no snapd"
+fi
+
+echo "─ core subsystems ─────────────────────────────────────"
+if have_file "usr/local/sbin/arcline-snapshot"; then
+  ok "btrfs snapshot tooling present"
+else
+  bad "missing arcline-snapshot"
+fi
+have_file "usr/local/sbin/arcline-rollback" \
+  && ok "btrfs rollback tooling present" || bad "missing arcline-rollback"
+have_file "usr/lib/systemd/system/arcline-snapshot.timer" \
+  && ok "snapshot timer unit present" || bad "missing arcline-snapshot.timer"
+
+grep -qi 'arcline' "$ROOTFS/etc/arcline-release" 2>/dev/null \
+  && ok "arcline-release present" || bad "missing /etc/arcline-release"
+
+echo "─ summary ─────────────────────────────────────────────"
+echo "  $pass passed, $fail failed"
+[[ $fail -eq 0 ]]