feat(admin): art-design-pro integration with local session auth

P1b Task 9: apps/admin based on art-design-pro v3.0.2 (tag, commit
d224dd4; source recorded in apps/admin/SOURCE.md), trimmed to
layout/login/i18n/request/table-form core. Login wired to real
POST /v1/auth/password (single-token session), Bearer header on all
requests, 401 interceptor logout+redirect, request-driven sliding
renewal (refresh at ~80% TTL, single-flight), best-effort
POST /v1/auth/logout on user-menu logout. One protected stub page
(相册管理). Dev port 5176 strictPort + /v1 proxy to 8080. Admin keeps
its own eslint9 flat config; root eslint ignores apps/admin/**.
vitest unit tests for renewal pacing + Playwright e2e (guard redirect,
localized wrong-password error, login lands on stub, token persists
across reload, logout clears session).

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

apps/admin/.env.example

@@ -0,0 +1,20 @@
+# 【@photo/admin 环境变量样例】复制为 .env 使用（.env 不入库，仓库约定）。
+# 所有键均有代码兜底，缺省也能构建运行；dev 端口(5176)与 /v1 代理在 vite.config.ts 固定。
+
+# 版本号（注入 __APP_VERSION__，用于 localStorage 版本化键前缀）
+VITE_VERSION = 0.1.0
+
+# 应用部署基础路径（如部署在子目录 /admin，则设置为 /admin/）
+VITE_BASE_URL = /
+
+# 权限模式（模板遗留键；@photo/admin 裁剪后仅前端路由表模式）
+VITE_ACCESS_MODE = frontend
+
+# 跨域请求时是否携带 Cookie（开启前需确保后端支持）
+VITE_WITH_CREDENTIALS = false
+
+# 是否打开路由信息
+VITE_OPEN_ROUTE_INFO = false
+
+# 锁屏加密密钥
+VITE_LOCK_ENCRYPT_KEY = change-me-lock-key