- Remove the Docker host-path 'Copy path on host' button and all of its
  path-resolution logic. It was environment-specific (host bind mounts) and
  not meaningful on a generic Piwigo install; that feature now lives in the
  personal plugin instead. Photo Nav is now purely generic prev/next.
- Add marketplace scaffolding: GPLv3 LICENSE.txt, README, en_UK language
  pack + description.txt, and index.php guards.
- Bump version to 16.2.0 (header + PHOTO_NAV_VERSION); set author.