nautd/webui: scripting, labels, settings, set-location, pause fix

Session checkpoint on webui-plugin:
- engine dump (nautctl dump) + engine endgame integration
- per-file move locations persistence; torrent-level "Set location"
  with reset/keep-relative/leave-separate handling + residual prune
- Lua: naut.get_labels, define_settings/get_setting (script_host struct)
- daemon-owned labels (category+tags) + taxonomy persistence; webui write-through
- fix: pausing a completed/seeding torrent now sticks (stop wins over result)
- automation tab responsive layout; anime_sort label gating + settings

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitignore

@@ -14,4 +14,6 @@ compile_commands.json
 /package/
 /package.zip
 # Stray torrents dropped at the repo root (fixtures under tests/ stay tracked)
-torrents/*.torrent
+torrents/*.torrent
+# Downloaded torrent data (capital-D dir used at runtime)
+/Downloads/