feat: add healthcheck configuration for app service in docker-compose

docker-compose.yml

@@ -1,7 +1,3 @@
-# docker-compose.yml
-# Production deployment: SvelteKit app + PostgreSQL
-# Usage: docker compose up -d
-
 services:
   db:
     image: postgres:17
@@ -39,6 +35,12 @@ services:
       NODE_ENV: production
     env_file:
       - .env
+    healthcheck:
+      test: ["CMD", "bun", "-e", "fetch('http://localhost:3000/api/health').then(r=>{if(!r.ok)process.exit(1)}).catch(()=>process.exit(1))"]
+      interval: 5s
+      timeout: 3s
+      retries: 3
+      start_period: 10s
 
 volumes:
   pgdata: