fix: add gosu to hermes + ssh host key to honcho builder

Hermes: install gosu package so run-multi-gateways.sh's gosu hermes
drop works when USER hermes is set in Dockerfile.

Honcho: add openssh-client + ssh-keyscan to openconcho-builder stage
so SSH host key verification passes during Gitea clone on first build.

ai/hermes/Dockerfile

@@ -13,6 +13,7 @@ FROM nousresearch/hermes-agent:latest
 USER root
 RUN apt-get update && \
     apt-get install -y --no-install-recommends \
+        gosu \
         libportaudio2 ca-certificates poppler-utils imagemagick \
         libolm-dev \
         texlive-latex-base texlive-latex-extra texlive-fonts-recommended \