[Agent] Replace dockerapi container with Redis-based control bus

data/Dockerfiles/host-agent/Dockerfile

@@ -0,0 +1,21 @@
+# host-agent: dedicated container that reads /host/proc to publish host-level
+# stats and answer exec.df / exec.host-stats commands. Reuses the same agent
+# binary; behaviour selected via MAILCOW_AGENT_SERVICE=host.
+#
+# Requires:
+#   volumes:
+#     - /proc:/host/proc:ro
+#     - /:/host/rootfs:ro
+
+ARG AGENT_IMAGE=ghcr.io/mailcow/agent:1.0
+
+FROM ${AGENT_IMAGE} AS agent
+
+FROM alpine:3.20
+RUN apk add --no-cache ca-certificates tzdata
+COPY --from=agent /out/mailcow-agent /usr/local/bin/mailcow-agent
+COPY --from=agent /out/mailcow-agent-cli /usr/local/bin/mailcow-agent-cli
+
+ENV MAILCOW_AGENT_SERVICE=host
+
+ENTRYPOINT ["/usr/local/bin/mailcow-agent"]