test(e2e): p1b cross-frontend playwright journey

- viewer playwright.config: third webServer boots admin dev (5176,
  reuseExisting) so one config serves both frontends
- journey.spec.ts: admin UI (login, zh+en album, real-jpeg banner via
  file chooser, category, staffB invite by account search, logout) ->
  staffB API uploads x3 (init/presign-PUT/complete) -> worker
  PublishService.processPhoto x3 -> public list verify -> viewer UI
  (banner bytes, zh->en switch, waterfall 3, chip filter 1, lightbox
  zoom/close, deep link) -> admin hide -> viewer 2 + hidden deep-link
  404 notice -> empty album state
- cleanup: journey album domain rows + staffB account via Prisma

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

apps/viewer/playwright.config.ts

@@ -3,6 +3,8 @@ import { defineConfig, devices } from '@playwright/test';
 // Task 6 起 e2e 打真实后端：webServer 先等 API（8080，仓库根 `pnpm dev:api`
 // 构建+启动；已在跑的实例直接复用），再等 viewer dev（5175，/v1 代理 → 8080）。
 // compose 基础设施（MySQL/MinIO/Redis）需预先 `docker compose up -d`（计划约定）。
+// Task 11 起跨端联调：第三个 webServer 一并等 admin dev（5176，/v1 代理 → 8080，
+// 同样复用已在跑的实例）——journey.spec.ts 以绝对 baseURL 驱动 admin 腿。
 export default defineConfig({
   testDir: './e2e',
   timeout: 30_000,
@@ -27,5 +29,12 @@ export default defineConfig({
       reuseExistingServer: true,
       timeout: 60_000,
     },
+    {
+      command: 'pnpm run dev',
+      cwd: '../admin',
+      url: 'http://127.0.0.1:5176',
+      reuseExistingServer: true,
+      timeout: 120_000, // 首次含模板依赖预构建
+    },
   ],
 });