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>

RESTART_FRONTEND_CLEAN.bat

@@ -0,0 +1,32 @@
+@echo off
+echo ========================================
+echo 清除快取並重啟前端服務
+echo ========================================
+
+cd /d %~dp0frontend
+
+echo.
+echo [1/4] 刪除 .next 快取目錄...
+if exist .next rmdir /s /q .next
+if exist .next\cache rmdir /s /q .next\cache
+
+echo.
+echo [2/4] 刪除 node_modules/.cache...
+if exist node_modules\.cache rmdir /s /q node_modules\.cache
+
+echo.
+echo [3/4] 等待 3 秒...
+timeout /t 3 /nobreak > nul
+
+echo.
+echo [4/4] 啟動開發伺服器 (Port 10180)...
+echo.
+echo ========================================
+echo 前端服務將在 http://10.1.0.245:10180 啟動
+echo 按 Ctrl+C 停止服務
+echo ========================================
+echo.
+
+npm run dev
+
+pause