Adds a profile-gated compose overlay defining `postgres-federated`
(pgvector/pgvector:pg17, port 5433) and `valkey-federated`
(valkey/valkey:8-alpine, port 6380) with named volumes
(`pg_federated_data`, `valkey_federated_data`), healthchecks identical
to the base stack, and the existing `infra/pg-init` mount so the vector
extension is created automatically on first boot.
Both services are gated by `profiles: [federated]` so they never start
on a plain `docker compose up`. Usage:
docker compose -f docker-compose.federated.yml --profile federated up -d
The overlay is mutually exclusive with the base dev stack on host ports
5433/6380 (header comment documents this). Base file untouched.
Refs #460
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
