fix(auth-service): add python3/make/g++ to builder stage for bcrypt

The bcrypt package requires native compilation. Added build dependencies
to the builder stage so npm ci can compile bcrypt successfully.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/auth-service/Dockerfile

@@ -6,6 +6,9 @@
 FROM node:20-alpine AS builder
 WORKDIR /app
 
+# 安装 bcrypt 编译所需的依赖
+RUN apk add --no-cache python3 make g++
+
 COPY package*.json ./
 COPY tsconfig*.json ./
 COPY prisma ./prisma/