The previous depName (forgejo.ellis.link/continuwuation/-/packages/container/continuwuity/)
was a Forgejo web UI path, not the Docker image name. Renovate's docker datasource
needs the image name as used in `docker pull`.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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