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.

actions/tiers/useradd.py

@@ -70,5 +70,7 @@ def _inject_env(ctx, env_path, uid, gid, shared_gid):
         new = re.sub(re.escape(START) + r".*?" + re.escape(END) + r"\n", block, text, flags=re.S)
     else:
         new = block + "\n" + text
-    ctx.host.write_file(actual, new, backup=True, sudo=True)
+    # backup=False: bash never left copies; a timestamped .bak would pile up a
+    # secret-bearing .env duplicate per run next to the bind-mounted project dir.
+    ctx.host.write_file(actual, new, backup=False, sudo=True)
     ctx.log.success(f"Updated {actual} with APEX_UID/GID/SHARED_GID")