fix: 创建缺失的E2E测试分层配置文件

问题根本原因:
- e2e/playwright.config.tiered.ts 文件不存在
- CI Pipeline的e2e-standard步骤引用了该配置文件
- 导致E2E测试无法执行

修复方案:
- 创建 playwright.config.tiered.ts 配置文件
- 支持三个测试层级: fast/standard/deep
- 根据TEST_TIER环境变量动态调整配置
  - fast: 15s超时, 0重试, 2并发
  - standard: 30s超时, 1重试, 1并发
  - deep: 60s超时, 2重试, 1并发

验证:
- 配置文件语法正确
- 支持环境变量配置

Ralph Loop #2 完成

e2e/playwright.config.tiered.ts

@@ -0,0 +1,52 @@
+import { defineConfig, devices } from '@playwright/test';
+
+const testTier = process.env.TEST_TIER || 'standard';
+
+const tierConfig = {
+  fast: {
+    timeout: 15000,
+    retries: 0,
+    workers: 2,
+  },
+  standard: {
+    timeout: 30000,
+    retries: 1,
+    workers: 1,
+  },
+  deep: {
+    timeout: 60000,
+    retries: 2,
+    workers: 1,
+  },
+};
+
+const config = tierConfig[testTier] || tierConfig.standard;
+
+export default defineConfig({
+  testDir: './',
+  fullyParallel: false,
+  forbidOnly: !!process.env.CI,
+  retries: config.retries,
+  workers: config.workers,
+  timeout: config.timeout,
+  reporter: [
+    ['html', { outputFolder: 'reports/html', open: 'never' }],
+    ['json', { outputFile: 'reports/results.json' }],
+    ['list']
+  ],
+  use: {
+    baseURL: process.env.BASE_URL || 'https://novalon.cn',
+    trace: 'on-first-retry',
+    screenshot: 'only-on-failure',
+    video: 'retain-on-failure',
+    launchOptions: {
+      args: ['--disable-dev-shm-usage', '--no-sandbox']
+    }
+  },
+  projects: [
+    {
+      name: 'chromium',
+      use: { ...devices['Desktop Chrome'] },
+    },
+  ],
+});