feat: 新增多个电力集团采购平台爬虫

- 新增4个电力集团采购平台爬虫：
  * 中国大唐集团电子商务平台 (CdtCrawler)
  * 大连能源采购平台 (CeicCrawler)
  * 华润守正采购交易平台 (SzecpCrawler)
- 更新 BidCrawlerService，集成新的爬虫到爬虫任务中
- 添加环境变量示例文件 .env.example，包含数据库和代理配置
- 优化 .env 文件，添加代理配置示例
- 为所有新爬虫添加完整的单元测试文件
- 使用与现有爬虫相同的反检测策略（人类行为模拟）
- 支持分页抓取，每个平台最多抓取5页数据
- 统一的错误处理机制，单个爬虫失败不影响其他爬虫执行

src/crawler/services/ceic_target.spec.ts

@@ -0,0 +1,61 @@
+import { CeicCrawler } from './ceic_target';
+import * as puppeteer from 'puppeteer';
+
+// Increase timeout to 120 seconds for manual inspection and slow sites
+jest.setTimeout(120000);
+
+describe('CeicCrawler Real Site Test', () => {
+  let browser: puppeteer.Browser;
+
+  beforeAll(async () => {
+    browser = await puppeteer.launch({
+      headless: false, // Run in non-headless mode
+      args: [
+        '--no-sandbox',
+        '--disable-setuid-sandbox',
+        '--disable-blink-features=AutomationControlled',
+        '--window-size=1920,1080',
+        '--disable-infobars',
+      ],
+      defaultViewport: null
+    });
+  });
+
+  afterAll(async () => {
+    if (browser) {
+      // Keep open for a few seconds after test to see result
+      await new Promise(r => setTimeout(r, 50000));
+      await browser.close();
+    }
+  });
+
+  it('should visit website and list all found bid information', async () => {
+    console.log(`
+Starting crawl for: ${CeicCrawler.name}`);
+    console.log(`Target URL: ${CeicCrawler.url}`);
+    
+    const results = await CeicCrawler.crawl(browser);
+    
+    console.log(`
+Successfully found ${results.length} items:
+`);
+    console.log('----------------------------------------');
+    results.forEach((item, index) => {
+      console.log(`${index + 1}. [${item.publishDate.toLocaleDateString()}] ${item.title}`);
+      console.log(`   Link: ${item.url}`);
+      console.log('----------------------------------------');
+    });
+
+    expect(results).toBeDefined();
+    expect(Array.isArray(results)).toBeTruthy();
+    
+    if (results.length === 0) {
+      console.warn('Warning: No items found. Observe browser window to see if content is loading or if there is a verification challenge.');
+    } else {
+       const firstItem = results[0];
+       expect(firstItem.title).toBeTruthy();
+       expect(firstItem.url).toMatch(/^https?:\/\//);
+       expect(firstItem.publishDate).toBeInstanceOf(Date);
+    }
+  });
+});