fix: resolve 17 confirmed bash-parity drifts from port review

Adversarial parity review of every ported action against its bash source
confirmed 17 real behavioral drifts (of 22 claimed); all fixed here:

- tiers/chown: defaults were compositions/apex/tierN (one level too deep);
  now the tier roots. shared/ base reset is non-recursive again.
- compose: --dry-run was swallowed by argparse.REMAINDER; now stripped.
- host.write_file: rendered files land 0644 (tempfile's 0600 made fresh
  systemd units/crowdsec configs owner-only).
- systemd.deploy_units: top-level non-hidden files only.
- ufw: missing docker/host config dir exits 66; missing /etc/ufw target
  aborts; empty rules dir warns; dotfile .rules excluded.
- sync/packages: Telegram error-trap parity and failed notify exits 1.
  Same notify-failure exit for backup/run and sync/repository.
  repository regains the node-dir guard.
- tiers/useradd: no more secret-bearing .env.bak per run.
- tiers/link: EOF on confirm prompt declines and continues.
- extract-traefik-certs: sudo mkdir inside the notify envelope.
- generate-happ-subscriptions: realpath parent-exists guards + docker check.
- configure/crowdsec: bouncer install goes through install_packages.
- lint-docker-compose: malformed/unreadable anchor-IP inputs are lint errors.
- core compose: APEX_RESTIC_REPOSITORY now ?error; RESTIC_COMPRESSION
  per-node via APEX_RESTIC_COMPRESSION (default auto).
- sys.service_exists line-anchored; tpl docstring corrected.

compositions/apex/docker-compose.yml

@@ -38,13 +38,15 @@ services:
       - ${APEX_TIER_ROOT2}:/data/@tier2:ro
     environment:
       <<: *shared-environment
-      RESTIC_REPOSITORY: "${APEX_RESTIC_REPOSITORY}"
+      RESTIC_REPOSITORY: "${APEX_RESTIC_REPOSITORY?error}"
       RESTIC_PASSWORD: "${APEX_RESTIC_PASSWORD?error}"
       AWS_ACCESS_KEY_ID: "${APEX_RESTIC_AWS_ACCESS_KEY_ID?error}"
       AWS_SECRET_ACCESS_KEY: "${APEX_RESTIC_AWS_SECRET_ACCESS_KEY?error}"
       AWS_REGION: "ru-central1"
       AWS_ENDPOINT_URL: "https://storage.yandexcloud.net/"
-      RESTIC_COMPRESSION: "auto"
+      # per-node override (icarus historically ran "max" for manual invocations;
+      # scheduled backups always force --compression auto on the CLI)
+      RESTIC_COMPRESSION: "${APEX_RESTIC_COMPRESSION:-auto}"
       RESTIC_CACHE_DIR: /var/restic-cache
     network_mode: "host"
     entrypoint: ["restic"]