build(docker): 优化Dockerfile使用多阶段构建并减少镜像大小

使用多阶段构建分离编译环境和运行环境，减少最终镜像大小
移除不必要的工具安装，仅保留运行时所需依赖

Dockerfile

@@ -1,13 +1,18 @@
-FROM golang:1.21-alpine
-
+FROM golang:1.21-alpine AS builder
 ENV CGO_ENABLED=0
+ENV GO111MODULE=on
 ENV GOPROXY=https://goproxy.cn,direct
-
-# 安装必要的工具
-RUN apk add --no-cache git tzdata bash curl
-
+RUN apk add --no-cache git tzdata
+WORKDIR /app
+COPY server/go.mod server/go.sum ./server/
 WORKDIR /app/server
+RUN go mod download
+COPY server/ ./
+RUN go build -o /out/server ./cmd/server/main.go
 
+FROM alpine:3.19
+RUN apk add --no-cache tzdata ca-certificates curl bash
+WORKDIR /app
+COPY --from=builder /out/server /app/server
 EXPOSE 8077
-
-CMD ["go", "run", "cmd/server/main.go"]
+ENTRYPOINT ["/app/server"]