chore(docker): 删除阿里云 Alpine 镜像源配置

- 移除了 Dockerfile 中配置的 Alpine 镜像中国区镜像源
- 保持默认 Alpine 仓库以简化源配置
- 优化 Dockerfile 代码结构，减少冗余配置
- 维持基础镜像和依赖安装逻辑不变

kami-gateway/Dockerfile.base

@@ -11,10 +11,6 @@ ENV TZ=Asia/Shanghai \
     GOOS=linux \
     GOARCH=amd64
 
-# Set up Alpine repositories (use China mirror for faster downloads)
-RUN echo "https://mirrors.aliyun.com/alpine/v3.22/main/" > /etc/apk/repositories && \
-    echo "https://mirrors.aliyun.com/alpine/v3.22/community/" >> /etc/apk/repositories
-
 # Install all dependencies
 RUN apk update && \
     apk upgrade && \