chore: rename postgres service to db

docs/deployment.md

@@ -33,6 +33,10 @@ development.
 `PUBLIC_CMS_API_URL` must be reachable by Astro; within Compose it is
 `http://backend:8000`.
 
+The PostgreSQL Compose service is `db`, so new `DATABASE_URL` values use `db:5432`.
+The internal `postgres` alias is retained only for compatibility with existing local
+`.env` files and should not be used in new configuration.
+
 The local virtual host is HTTP-only. Production must publish NGINX through the intended
 network interface, configure DNS for `azionelab.org`, terminate TLS, and prevent direct
 external access to application ports.

docs/operations.md

@@ -5,7 +5,7 @@
 ```bash
 docker compose up --build -d
 docker compose ps
-docker compose logs -f proxy backend frontend postgres
+docker compose logs -f proxy backend frontend db
 docker compose down
 ```
 
@@ -33,7 +33,7 @@ Back up the database and media at the same logical point in time:
 ```bash
 mkdir -p backups/media
 docker compose stop frontend backend
-docker compose exec -T postgres sh -c 'pg_dump -U "$POSTGRES_USER" "$POSTGRES_DB"' > backups/database.sql
+docker compose exec -T db sh -c 'pg_dump -U "$POSTGRES_USER" "$POSTGRES_DB"' > backups/database.sql
 docker compose cp backend:/app/media/. backups/media/
 docker compose start backend frontend
 ```

docs/runbook.md

@@ -4,7 +4,7 @@
 
 1. Check `docker compose ps` and the backend health status.
 2. Request `http://azionelab.org:8080/api/site/home/` through NGINX.
-3. Inspect `docker compose logs backend postgres`.
+3. Inspect `docker compose logs backend db`.
 4. Verify `PUBLIC_CMS_API_URL` resolves from the frontend container.
 5. Restart the frontend after recovery so its static page is rebuilt from CMS data.