feat(infra): add PostgreSQL provider switch (soft migration, default SqlServer) + local postgres:17 service

src/GreenHome.Api/docker-compose.yaml

@@ -33,7 +33,24 @@ services:
     networks:
       - greenNetwork
 
+  postgres:
+    image: postgres:17-alpine
+    restart: unless-stopped
+    environment:
+      POSTGRES_DB: greenhome
+      POSTGRES_USER: greenhome
+      POSTGRES_PASSWORD: greenhome
+    ports:
+      - "5432:5432"
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    networks:
+      - greenNetwork
+
 networks:
   serviceNetwork:
     name: greenNetwork
     external: true
+
+volumes:
+  pgdata: