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>

tests/fixtures/phase7.lua

@@ -3,5 +3,8 @@ function on_torrent_finished(event)
 end
 
 function on_file_complete(event)
-    naut.move_file(event.torrent_id, event.index, event.path .. ".moved")
+    -- Labels surface to Lua as a plain array of strings; use the first to route.
+    local labels = naut.get_labels(event.torrent_id)
+    local suffix = labels[1] or "moved"
+    naut.move_file(event.torrent_id, event.index, event.path .. "." .. suffix)
 end