feat: 添加生产环境部署工作流和相关文档

backend/compose.prod.yaml

@@ -0,0 +1,22 @@
+name: ballet-island
+
+services:
+  api:
+    image: ballet-island-api:${IMAGE_TAG:?Set IMAGE_TAG to the Git commit}
+    build:
+      context: .
+    restart: unless-stopped
+    environment:
+      HTTP_ADDR: :8080
+      DATABASE_URL: ${DATABASE_URL:?Set DATABASE_URL to the production PostgreSQL URL}
+      WECHAT_APP_ID: ${WECHAT_APP_ID:?Set WECHAT_APP_ID}
+      WECHAT_APP_SECRET: ${WECHAT_APP_SECRET:?Set WECHAT_APP_SECRET}
+    ports:
+      - "127.0.0.1:8080:8080"
+    healthcheck:
+      test: ["CMD", "wget", "-q", "-T", "3", "-O", "/dev/null", "http://127.0.0.1:8080/readyz"]
+      interval: 10s
+      timeout: 5s
+      retries: 3
+      start_period: 10s
+    stop_grace_period: 15s