The base image never starts a service (closes #16)

build.sh and bin/test used to start valkey-server and ping it to prove it runs;
they now check it with valkey-server --version and valkey-cli --version, so the
ping loop, shutdown, and the cleanup of the Valkey run's log files are gone.
/var/log/valkey and /var/log/nginx keep their package owners and modes, and
nginx -t stays. README states that Valkey, PostgreSQL and nginx are installed
but never run. No package install starts a service: invoke-rc.d already denies
every start, and no ENTRYPOINT or CMD starts one.

Model: deepseek-v4-pro

bin/test

@@ -34,9 +34,6 @@ docker run --rm "$img" bash -ec '
     bundle --version
     valkey-server --version
     valkey-cli --version
-    valkey-server /etc/valkey/valkey.conf
-    ok=; for i in $(seq 1 50); do if valkey-cli ping 2>/dev/null | grep -q PONG; then ok=1; break; fi; sleep 0.1; done; [ -n "$ok" ]
-    valkey-cli shutdown nosave
     psql --version
     postgres --version
     nginx -t