feat(backend): Day 5 - backend basic architecture setup completed

backend/src/config/env.ts

@@ -0,0 +1,36 @@
+import { config as dotenvConfig } from 'dotenv';
+
+dotenvConfig();
+
+export const config = {
+  // 服务器配置
+  nodeEnv: process.env.NODE_ENV || 'development',
+  port: parseInt(process.env.PORT || '3001', 10),
+  host: process.env.HOST || '0.0.0.0',
+
+  // 数据库配置
+  databaseUrl: process.env.DATABASE_URL || '',
+
+  // Redis配置
+  redisUrl: process.env.REDIS_URL || 'redis://localhost:6379',
+
+  // JWT配置
+  jwtSecret: process.env.JWT_SECRET || 'your-secret-key',
+
+  // 大模型API Keys
+  deepseekApiKey: process.env.DEEPSEEK_API_KEY || '',
+  qwenApiKey: process.env.QWEN_API_KEY || '',
+  geminiApiKey: process.env.GEMINI_API_KEY || '',
+
+  // Dify配置
+  difyApiUrl: process.env.DIFY_API_URL || 'http://localhost:5001',
+  difyApiKey: process.env.DIFY_API_KEY || '',
+
+  // 文件上传配置
+  uploadMaxSize: parseInt(process.env.UPLOAD_MAX_SIZE || '10485760', 10),
+  uploadDir: process.env.UPLOAD_DIR || './uploads',
+
+  // 日志配置
+  logLevel: process.env.LOG_LEVEL || 'info',
+};
+