feat: HR Portal - Complete Multi-Tenant System with Redis Session Storage

Major Features:
- ✅ Multi-tenant architecture (tenant isolation)
- ✅ Employee CRUD with lifecycle management (onboarding/offboarding)
- ✅ Department tree structure with email domain management
- ✅ Company info management (single-record editing)
- ✅ System functions CRUD (permission management)
- ✅ Email account management (multi-account per employee)
- ✅ Keycloak SSO integration (auth.lab.taipei)
- ✅ Redis session storage (10.1.0.254:6379)
  - Solves Cookie 4KB limitation
  - Cross-system session sharing
  - Sliding expiration (8 hours)
  - Automatic token refresh

Technical Stack:
Backend:
- FastAPI + SQLAlchemy
- PostgreSQL 16 (10.1.0.20:5433)
- Keycloak Admin API integration
- Docker Mailserver integration (SSH)
- Alembic migrations

Frontend:
- Next.js 14 (App Router)
- NextAuth 4 with Keycloak Provider
- Redis session storage (ioredis)
- Tailwind CSS

Infrastructure:
- Redis 7 (10.1.0.254:6379) - Session + Cache
- Keycloak 26.1.0 (auth.lab.taipei)
- Docker Mailserver (10.1.0.254)

Architecture Highlights:
- Session管理由 Keycloak + Redis 統一控制
- 支援多系統 (HR/WebMail/Calendar/Drive/Office) 共享 session
- Token 自動刷新,異質服務整合
- 未來可無縫遷移到雲端

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

frontend/vitest.setup.ts

@@ -0,0 +1,24 @@
+import { expect, afterEach, vi } from 'vitest'
+import { cleanup } from '@testing-library/react'
+import * as matchers from '@testing-library/jest-dom/matchers'
+
+// Extend Vitest's expect with jest-dom matchers
+expect.extend(matchers)
+
+// Cleanup after each test
+afterEach(() => {
+  cleanup()
+})
+
+// Mock Next.js router
+vi.mock('next/navigation', () => ({
+  useRouter: () => ({
+    push: vi.fn(),
+    replace: vi.fn(),
+    prefetch: vi.fn(),
+  }),
+  useSearchParams: () => ({
+    get: vi.fn(),
+  }),
+  usePathname: () => '/',
+}))