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/package.json

@@ -0,0 +1,45 @@
+{
+  "name": "frontend",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start",
+    "lint": "eslint",
+    "test": "vitest",
+    "test:ui": "vitest --ui",
+    "test:coverage": "vitest --coverage"
+  },
+  "dependencies": {
+    "@auth/upstash-redis-adapter": "^2.11.1",
+    "@tanstack/react-query": "^5.90.21",
+    "@upstash/redis": "^1.36.2",
+    "axios": "^1.13.5",
+    "ioredis": "^5.9.3",
+    "keycloak-js": "^26.2.3",
+    "next": "^15.5.12",
+    "next-auth": "^4.24.11",
+    "react": "19.2.3",
+    "react-dom": "19.2.3"
+  },
+  "devDependencies": {
+    "@tailwindcss/postcss": "^4",
+    "@testing-library/dom": "^10.4.0",
+    "@testing-library/jest-dom": "^6.6.3",
+    "@testing-library/react": "^16.0.1",
+    "@testing-library/user-event": "^14.5.1",
+    "@types/node": "^20",
+    "@types/react": "^19",
+    "@types/react-dom": "^19",
+    "@vitejs/plugin-react": "^4.3.4",
+    "@vitest/coverage-v8": "^2.1.8",
+    "@vitest/ui": "^2.1.8",
+    "eslint": "^9",
+    "eslint-config-next": "^15.5.12",
+    "jsdom": "^25.0.1",
+    "tailwindcss": "^4",
+    "typescript": "^5",
+    "vitest": "^2.1.8"
+  }
+}