chore(docker): refine compose for named volume server deploy

Use a named SQLite volume, healthcheck, and clearer production env examples.

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.docker.example

@@ -1,5 +1,7 @@
-# Copy to .env.docker for docker compose (gitignored).
-# Do not commit real secrets.
-
-JWT_SECRET=replace-with-a-strong-secret
-CORS_ORIGIN=http://localhost:5174
+# Copy to .env.docker on the server (never commit real secrets).
+#
+# Required in production:
+JWT_SECRET=replace-with-a-long-random-secret
+#
+# Frontend origin (your deployed Vue app URL):
+CORS_ORIGIN=https://your-frontend-domain.example

docker-compose.yml

@@ -3,9 +3,10 @@ services:
     build:
       context: .
       dockerfile: Dockerfile
+    image: child-gold-land-backend:latest
     container_name: child-gold-land-backend
     ports:
-      - "3000:3000"
+      - "${PORT:-3000}:3000"
     env_file:
       - .env.docker
     environment:
@@ -14,5 +15,23 @@ services:
       HOST: 0.0.0.0
       DB_PATH: /app/data/app.db
     volumes:
-      - ./docker-data:/app/data
+      # Persistent SQLite storage (WAL/SHM live here too).
+      # On server, replace with e.g. /var/lib/child-gold-land/data:/app/data
+      - sqlite_data:/app/data
     restart: unless-stopped
+    healthcheck:
+      test:
+        [
+          "CMD",
+          "node",
+          "-e",
+          "fetch('http://127.0.0.1:3000/health').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))",
+        ]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+      start_period: 20s
+
+volumes:
+  sqlite_data:
+    name: child-gold-land-sqlite