chore: 添加 Docker 部署配置

- Dockerfile: 多阶段构建（deps → build → runner）
- docker-compose.yml: 一键部署，数据持久化到 volume
- next.config.ts: output standalone 模式
- .dockerignore: 排除 node_modules、.next、dev.db

docker-compose.yml

@@ -0,0 +1,19 @@
+services:
+  blog:
+    build: .
+    container_name: sui-blog
+    restart: unless-stopped
+    ports:
+      - "3000:3000"
+    environment:
+      - DATABASE_URL=file:/app/prisma/dev.db
+      - SESSION_SECRET=${SESSION_SECRET:-change-me-to-a-random-string}
+      - ADMIN_PASSWORD=${ADMIN_PASSWORD:-asui2026}
+      - AI_BASE_URL=${AI_BASE_URL:-https://api.openai.com/v1}
+      - AI_API_KEY=${AI_API_KEY:-}
+      - AI_MODEL=${AI_MODEL:-gpt-4o-mini}
+    volumes:
+      - blog-data:/app/prisma
+
+volumes:
+  blog-data: