Harden permissions, close exposed ports, and clean up tasks

- Quote file modes. Unquoted 644/755 were read as decimal, so files
  landed as 1204. Templates holding secrets are now 0640 root:docker.
- Stop publishing Authentik 9000/9443 and Karakeep 3000 (Caddy reaches
  them over the docker network), bind dir2opds to the Tailscale IP, and
  drop Caddy's unused 8448.
- Atuin login uses no_log and only runs once; the installer only runs
  when Atuin is missing.
- Make chsh, ufw-docker install, the bat symlink and Atuin dotfiles
  idempotent.
- Back up the Paperless data volume (SQLite DB), stopping Paperless
  during the backup.
- Close public sign-up on kosync and ByteStash.
- Replace hardcoded IPs and domains with variables.
- Remove teardown tasks and templates for 9 retired services.
- Fix the dockcheck comment: it auto-updates labelled containers.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

roles/cron/templates/dockcheck.config.j2

@@ -1,8 +1,10 @@
-# Dockcheck Configuration - Check only, no updates
-# Don't update, just check for updates
+# Dockcheck Configuration
+# Auto-updates containers labelled mag37.dockcheck.update=true, and sends a
+# Gotify notice for anything else with an update. Uncomment DontUpdate to
+# only check.
 # DontUpdate=true
 OnlyLabel=true
-AutoMode=true 
+AutoMode=true
 
 # Enable notifications
 Notify=true