feat : add Adminer service on port 8083

- Adminer web UI for PostgreSQL management
- Port 8083 (8080 taken by sirh-app)
- Nginx reverse proxy on adminer-prod.malio-dev.fr (HTTP)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -8,3 +8,14 @@ services:
     volumes:
       - ./data:/var/lib/postgresql/data
     restart: unless-stopped
+
+  adminer:
+    image: adminer:latest
+    container_name: adminer
+    ports:
+      - "8083:8080"
+    environment:
+      ADMINER_DEFAULT_SERVER: postgres
+    restart: unless-stopped
+    depends_on:
+      - postgres