feat: 实现RCU固件升级服务核心功能

- 添加升级服务主逻辑，包括定时触发升级、状态查询和日志记录
- 实现数据库初始化脚本和日志表结构
- 添加PM2部署配置文件
- 实现环境变量配置系统
- 添加API客户端模块处理外部接口调用
- 实现升级状态轮询和超时处理机制
- 添加测试用例验证核心功能

tests/apiClient.test.js

@@ -0,0 +1,9 @@
+const apiClient = require('../src/apiClient');
+
+describe('API Client', () => {
+    test('should be defined', () => {
+        expect(apiClient).toBeDefined();
+        expect(apiClient.triggerUpgrade).toBeDefined();
+        expect(apiClient.queryStatus).toBeDefined();
+    });
+});

tests/config.test.js

@@ -0,0 +1,17 @@
+const config = require('../src/config');
+
+describe('Config Loader', () => {
+    test('should load and parse UPGRADE_CONFIG correctly', () => {
+        expect(Array.isArray(config.upgradeConfig)).toBe(true);
+        const group = config.upgradeConfig[0];
+        expect(Array.isArray(group.hosts)).toBe(true);
+        expect(Array.isArray(group.roomtypes)).toBe(true);
+        expect(group.roomtypes.length).toBe(2);
+        expect(group.roomtypes[0]).toHaveProperty('roomtype_id');
+        expect(group.roomtypes[0]).toHaveProperty('fileName');
+    });
+
+    test('should have default cron schedule', () => {
+        expect(config.cronSchedule).toBeDefined();
+    });
+});