fix(docker): 修复 Dockerfile npm 构建错误并优化测试配置

- 修复 Dockerfile 使用 pnpm 替代 npm ci（适配 pnpm 迁移）
- 为 docker-compose-test.yml 添加自动构建配置
- 更新测试配置文档说明一键构建命令

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

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

Dockerfile

@@ -19,13 +19,16 @@ FROM ${NODE_IMAGE} AS frontend-builder
 
 WORKDIR /app/frontend
 
+# Install pnpm
+RUN corepack enable && corepack prepare pnpm@latest --activate
+
 # Install dependencies first (better caching)
-COPY frontend/package*.json ./
-RUN npm ci
+COPY frontend/package.json frontend/pnpm-lock.yaml ./
+RUN pnpm install --frozen-lockfile
 
 # Copy frontend source and build
 COPY frontend/ ./
-RUN npm run build
+RUN pnpm run build
 
 # -----------------------------------------------------------------------------
 # Stage 2: Backend Builder