refactor(Dockerfile): 移除中国镜像源配置以简化构建

构建环境已迁移至全球通用镜像源，不再需要特定中国镜像配置

Dockerfile

@@ -1,6 +1,4 @@
 FROM golang:1.21-alpine AS build
-ENV GOPROXY=https://goproxy.cn,direct
-RUN sed -i 's/dl-cdn.alpinelinux.org/mirrors.aliyun.com/g' /etc/apk/repositories
 WORKDIR /app
 RUN apk add --no-cache build-base
 COPY server/ ./server/
@@ -9,7 +7,6 @@ WORKDIR /app/server
 RUN go build -o /app/bin/marketing-data-server ./cmd/server
 
 FROM alpine:3.19
-RUN sed -i 's/dl-cdn.alpinelinux.org/mirrors.aliyun.com/g' /etc/apk/repositories
 WORKDIR /app
 COPY --from=build /app/bin/marketing-data-server /app/bin/marketing-data-server
 COPY --from=build /app/web /app/web