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>

scripts/COPY-AND-RUN.txt

@@ -0,0 +1,29 @@
+========================================
+請在 Ubuntu Server 上執行以下命令
+========================================
+
+1. 打開終端機/SSH 連接到 Ubuntu Server
+2. 複製以下 3 個命令 (全選後複製)
+3. 貼到終端機並按 Enter
+
+----------------------------------------
+命令開始 (請複製以下 3 行)
+----------------------------------------
+
+docker stop postgres && docker rm postgres && docker run -d --name postgres --restart unless-stopped -e POSTGRES_PASSWORD="DC1qaz2wsx" -e TZ=Asia/Taipei -p 0.0.0.0:5432:5432 -v postgres-data:/var/lib/postgresql/data postgres:16
+
+sleep 8 && docker exec postgres psql -U hr_user -d hr_portal -c "SELECT 'Database OK: ' || COUNT(*)::text || ' tables found' FROM information_schema.tables WHERE table_schema='public' AND table_type='BASE TABLE';"
+
+docker ps | grep postgres && docker port postgres
+
+----------------------------------------
+命令結束
+----------------------------------------
+
+完成後,你應該會看到:
+- Database OK: 9 tables found
+- postgres 容器運行中
+- 0.0.0.0:5432->5432/tcp
+
+然後回到這裡告訴我「完成」,我會測試連接!
+========================================