Scaffold repo: infra docker-compose, service layout, README

Sets up the microservice home-automation platform skeleton: docker-compose
for mosquitto/postgres/clickhouse/redis/rabbitmq, per-service README stubs
describing responsibilities, and top-level README with architecture/stack.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

services/health-check-service/README.md

@@ -0,0 +1,11 @@
+# health-check-service (Go)
+
+Status: not implemented yet. May start as a goroutine inside
+device-control-service and get split out into its own container later —
+kept as a separate directory from day one so the split is a non-event.
+
+Responsibility:
+- Periodically (ticker) check `last_seen` for every device in Redis.
+- When a device exceeds the offline timeout, flip its `status` to `offline`
+  and publish an event for notification-service.
+- Good place to demonstrate goroutines + graceful shutdown in Go.