fix(compose): use external postgres volume + city-service ENV

- docker-compose.yml: postgres uses microdao-daarion_postgres_data (external)
- docker-compose.yml: city-service connects to dagi-postgres:5432/daarion + NATS_URL
- docker-compose.city-space.yml: added dagi-postgres, dagi-nats as services
- docs/DEPLOY_ON_SERVER.md: added restart instructions without data loss

Closes TASK_PHASE_DOCKER_COMPOSE_CITY_SERVICE_POSTGRES

docker-compose.yml

@@ -156,7 +156,7 @@ services:
       timeout: 10s
       retries: 3
 
-  # PostgreSQL Database
+  # PostgreSQL Database (Production: external volume)
   postgres:
     image: postgres:15-alpine
     container_name: dagi-postgres
@@ -165,9 +165,9 @@ services:
     environment:
       - POSTGRES_USER=postgres
       - POSTGRES_PASSWORD=postgres
-      - POSTGRES_DB=daarion_memory
+      - POSTGRES_DB=daarion
     volumes:
-      - postgres-data:/var/lib/postgresql/data
+      - microdao-daarion_postgres_data:/var/lib/postgresql/data
       - ./services/memory-service/init.sql:/docker-entrypoint-initdb.d/init.sql
     networks:
       - dagi-network
@@ -348,8 +348,9 @@ services:
     ports:
       - "7001:7001"
     environment:
-      - DATABASE_URL=postgresql://postgres:postgres@postgres:5432/daarion_memory
+      - DATABASE_URL=postgresql://postgres:postgres@dagi-postgres:5432/daarion
       - MATRIX_GATEWAY_URL=http://gateway:9300
+      - NATS_URL=nats://dagi-nats:4222
       - LOG_LEVEL=INFO
     volumes:
       - ./logs:/app/logs
@@ -372,8 +373,9 @@ volumes:
     driver: local
   memory-data:
     driver: local
-  postgres-data:
-    driver: local
+  # Production: use existing external volume with all DAARION data
+  microdao-daarion_postgres_data:
+    external: true
   vision-model-cache:
     driver: local
   qdrant-data: