Add matrix_continuwuity_version with container_image_tag inheriting from it.
Rename all _docker_image* variables to _container_image* with deprecation notices.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* continuwuity support
* continuwuity support
* use main instead of commit tag
* fix docker image link
* migration from conduwuit
* fix yaml lint
* backup directories and linter fixes
* linter fixes