feat: 新增 Docker Compose 部署方案

- Dockerfile 单阶段 Alpine 镜像，使用国内镜像（npmmirror / Prisma 引擎 / apk）加速
- entrypoint 首次复制内置图章素材到 uploads volume，自动执行 prisma migrate deploy
- docker-compose.yml 绑定 127.0.0.1:3001，强制走外部 Nginx 反代
- Express 在 production 下同时托管 packages/web/dist 及 SPA fallback
- Prisma schema 增加 linux-musl 二进制目标，支持 Alpine 运行
- 新增 DEPLOY.md 部署指南，含 .env 模板与 Nginx 反代示例

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

packages/server/src/index.ts

@@ -31,6 +31,17 @@ app.use("/api/redemption", redemptionRoutes);
 // Admin routes
 app.use("/api/admin", adminRoutes);
 
+// Serve built web frontend in production (single-container deployment)
+if (process.env.NODE_ENV === "production") {
+  const webDist = path.join(__dirname, "../../web/dist");
+  app.use(express.static(webDist));
+  app.use((req, res, next) => {
+    if (req.method !== "GET" && req.method !== "HEAD") return next();
+    if (req.path.startsWith("/api") || req.path.startsWith("/uploads")) return next();
+    res.sendFile(path.join(webDist, "index.html"));
+  });
+}
+
 app.listen(PORT, () => {
   console.log(`Server running on http://localhost:${PORT}`);
 });