test: add 30 smoke tests for break detection across SaaS/Admin/Desktop

Layer 1 断裂探测矩阵:
- S1-S6: SaaS API 端到端 (auth/lockout/relay/permissions/billing/knowledge)
- A1-A6: Admin V2 连通性 (login/dashboard/CRUD/knowledge/roles/models)
- D1-D6: Desktop 聊天流 (gateway/kernel/relay/cancel/offline/error)
- F1-F6: Desktop 功能闭环 (agent/hands/pipeline/memory/butler/skills)
- X1-X6: 跨系统闭环 (provider→desktop/disabled user/knowledge/stats/totp/billing)

Also adds: admin-v2 Playwright config, updated spec doc with cross-reference

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

admin-v2/playwright.config.ts

@@ -0,0 +1,50 @@
+import { defineConfig, devices } from '@playwright/test';
+
+/**
+ * Admin V2 E2E 测试配置
+ *
+ * 断裂探测冒烟测试 — 验证 Admin V2 页面与 SaaS 后端的连通性
+ *
+ * 前提条件:
+ * - SaaS Server 运行在 http://localhost:8080
+ * - Admin V2 dev server 运行在 http://localhost:5173
+ * - 数据库有种子数据 (super_admin: testadmin/Admin123456)
+ */
+export default defineConfig({
+  testDir: './tests/e2e',
+  timeout: 60000,
+  expect: {
+    timeout: 10000,
+  },
+  fullyParallel: false,
+  retries: 0,
+  workers: 1,
+  reporter: [
+    ['list'],
+    ['html', { outputFolder: 'test-results/html-report' }],
+  ],
+  use: {
+    baseURL: 'http://localhost:5173',
+    trace: 'on-first-retry',
+    screenshot: 'only-on-failure',
+    video: 'retain-on-failure',
+    actionTimeout: 10000,
+    navigationTimeout: 30000,
+  },
+  projects: [
+    {
+      name: 'chromium',
+      use: {
+        ...devices['Desktop Chrome'],
+        viewport: { width: 1280, height: 720 },
+      },
+    },
+  ],
+  webServer: {
+    command: 'pnpm dev --port 5173',
+    url: 'http://localhost:5173',
+    reuseExistingServer: true,
+    timeout: 30000,
+  },
+  outputDir: 'test-results/artifacts',
+});