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>

backend/test_menu_tree_api.py

@@ -0,0 +1,45 @@
+"""
+測試功能列表樹狀結構 API
+"""
+import requests
+import json
+
+BASE_URL = "http://localhost:10181/api/v1"
+
+def test_menu_tree():
+    """測試取得選單樹狀結構"""
+
+    print("=" * 80)
+    print("測試 1: 系統管理公司 (is_sysmana=true)")
+    print("=" * 80)
+
+    response = requests.get(f"{BASE_URL}/system-functions/menu/tree?is_sysmana=true")
+
+    if response.status_code == 200:
+        tree = response.json()
+        print(f"Status: {response.status_code} OK")
+        print(f"Total root items: {len(tree)}")
+        print("\nMenu Tree:")
+        print(json.dumps(tree, indent=2, ensure_ascii=False))
+    else:
+        print(f"ERROR: {response.status_code}")
+        print(response.text)
+
+    print("\n" + "=" * 80)
+    print("測試 2: 一般租戶 (is_sysmana=false)")
+    print("=" * 80)
+
+    response = requests.get(f"{BASE_URL}/system-functions/menu/tree?is_sysmana=false")
+
+    if response.status_code == 200:
+        tree = response.json()
+        print(f"Status: {response.status_code} OK")
+        print(f"Total root items: {len(tree)}")
+        print("\nMenu Tree:")
+        print(json.dumps(tree, indent=2, ensure_ascii=False))
+    else:
+        print(f"ERROR: {response.status_code}")
+        print(response.text)
+
+if __name__ == "__main__":
+    test_menu_tree()