fix(构建): 支持配置基础镜像仓库

允许通过构建参数/脚本选项切换基础镜像来源，避免镜像源 403 影响构建

Dockerfile

@@ -6,10 +6,14 @@
 # Stage 3: Final minimal image
 # =============================================================================
 
+ARG NODE_IMAGE=node:24-alpine
+ARG GOLANG_IMAGE=golang:1.25-alpine
+ARG ALPINE_IMAGE=alpine:3.19
+
 # -----------------------------------------------------------------------------
 # Stage 1: Frontend Builder
 # -----------------------------------------------------------------------------
-FROM node:24-alpine AS frontend-builder
+FROM ${NODE_IMAGE} AS frontend-builder
 
 WORKDIR /app/frontend
 
@@ -24,7 +28,7 @@ RUN npm run build
 # -----------------------------------------------------------------------------
 # Stage 2: Backend Builder
 # -----------------------------------------------------------------------------
-FROM golang:1.25-alpine AS backend-builder
+FROM ${GOLANG_IMAGE} AS backend-builder
 
 # Build arguments for version info (set by CI)
 ARG VERSION=docker
@@ -56,7 +60,7 @@ RUN CGO_ENABLED=0 GOOS=linux go build \
 # -----------------------------------------------------------------------------
 # Stage 3: Final Runtime Image
 # -----------------------------------------------------------------------------
-FROM alpine:3.19
+FROM ${ALPINE_IMAGE}
 
 # Labels
 LABEL maintainer="Wei-Shaw <github.com/Wei-Shaw>"