ci(release): publish the missing roboco-agent-secretary image

The secretary agent image landed with the company layer (0.4.0) and is
built by docker-compose + referenced by the orchestrator, but the release
workflow's publish list was never updated, so it was absent from GHCR and
Docker Hub. Add it so a pull-based deploy has the full image set.

.github/workflows/release.yml

@@ -98,6 +98,7 @@ jobs:
             [roboco-agent-ux]=docker/agent-ux.Dockerfile
             [roboco-agent-doc]=docker/agent-doc.Dockerfile
             [roboco-agent-prompter]=docker/agent-prompter.Dockerfile
+            [roboco-agent-secretary]=docker/agent-secretary.Dockerfile
           )
           for name in "${!IMAGES[@]}"; do
             echo "::group::build ${name}"