Add restart: unless-stopped to db and app services

Automatically restarts both containers on crash or server reboot,
unless manually stopped with docker compose down.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -1,6 +1,7 @@
 services:
   db:
     image: postgres:16-alpine
+    restart: unless-stopped
     environment:
       POSTGRES_USER: ${POSTGRES_USER}
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
@@ -17,6 +18,7 @@ services:
 
   app:
     build: .
+    restart: unless-stopped
     ports:
       - "0.0.0.0:3000:3000"
     environment: