fix: use node:20-alpine and add taobao npm registry mirror

Dockerfile

@@ -1,4 +1,7 @@
-FROM node:22-alpine AS base
+FROM node:20-alpine AS base
+
+# 设置淘宝 npm 镜像
+RUN npm config set registry https://registry.npmmirror.com
 
 # --- Dependencies ---
 FROM base AS deps