Container logs: the fluentd address ignores DFE_BIND_HOST, and engine-added transform instances stay on json-file

[catinspace-au]

The container-logs overlay ships DFE's own stdout to the collector through Docker's fluentd driver. Four things in it are wrong or about to be.

• The driver dials ${DFE_CONTAINER_LOG_ADDRESS:-tcp://127.0.0.1:${DFE_OTEL_FLUENT_PORT:-24224}} (docker-compose.container-logs.yml), while the collector publishes 24224 on DFE_BIND_HOST (docker-compose.yml:1409). Move DFE_BIND_HOST off loopback and the logs stop, unless the operator knows to set DFE_CONTAINER_LOG_ADDRESS by hand. Default the address from DFE_BIND_HOST.
• The overlay lists services by name. A per_config transform instance the engine adds at runtime is not on the list, so it logs to json-file and never reaches dfe.otel_logs.
• The overlay header says docker compose logs cannot read back a fluentd-driven stream. The rc.14 review says that is wrong, because Docker's dual logging reads it back. Check it on the Docker we support, then fix the header and wherever the docs repeat it.
• config/otel-collector/config.yaml:33 uses the fluentforward receiver name, which the collector warns is a deprecated alias.

Done when a stack with DFE_BIND_HOST off loopback and an engine-added transform instance shows both in dfe.otel_logs, and the docs say what docker compose logs really does.