fix(mpc-service): 改用 Debian slim 基础镜像

- 从 Alpine 改为 Debian slim (与 identity-service 一致)
- 使用 curl 进行健康检查
- 添加 DATABASE_URL 用于 Prisma generate
- 通过代理访问官方源

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/services/mpc-service/Dockerfile

@@ -2,7 +2,7 @@
 # MPC Party Service Dockerfile
 # =============================================================================
 
-# Build stage
+# Build stage - use Alpine for smaller build context
 FROM node:20-alpine AS builder
 
 WORKDIR /app
@@ -25,13 +25,19 @@ COPY src ./src
 # Build TypeScript
 RUN npm run build
 
-# Production stage
-FROM node:20-alpine
+# Verify build output exists
+RUN ls -la dist/ && test -f dist/main.js
+
+# Production stage - use Debian slim for OpenSSL compatibility
+FROM node:20-slim
 
 WORKDIR /app
 
-# Install OpenSSL for Prisma (Alpine 3.22 uses OpenSSL 3)
-RUN apk add --no-cache openssl
+# Install OpenSSL and curl for health checks
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    openssl \
+    curl \
+    && rm -rf /var/lib/apt/lists/*
 
 # Install production dependencies only
 COPY package*.json ./
@@ -39,14 +45,14 @@ RUN npm ci --only=production
 
 # Copy Prisma schema and generate client
 COPY prisma ./prisma/
-RUN npx prisma generate
+RUN DATABASE_URL="postgresql://user:pass@localhost:5432/db" npx prisma generate
 
 # Copy built files
 COPY --from=builder /app/dist ./dist
 
 # Create non-root user
-RUN addgroup -g 1001 -S nodejs && \
-    adduser -S nestjs -u 1001
+RUN groupadd -g 1001 nodejs && \
+    useradd -u 1001 -g nodejs nestjs
 
 # Create temp directory for TSS
 RUN mkdir -p /tmp/tss && chown -R nestjs:nodejs /tmp/tss
@@ -59,7 +65,7 @@ EXPOSE 3006
 
 # Health check
 HEALTHCHECK --interval=30s --timeout=3s --start-period=40s --retries=3 \
-  CMD node -e "require('http').get('http://localhost:3006/api/v1/health', (r) => {process.exit(r.statusCode === 200 ? 0 : 1)})"
+  CMD curl -f http://localhost:3006/api/v1/health || exit 1
 
 # Start service
 CMD ["node", "dist/main.js"]