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/create_tenant_employees_view.py

@@ -0,0 +1,82 @@
+"""
+建立 tenant_employees 視圖
+整合 tenant_emp_settings 和 tenant_emp_resumes 的資料
+"""
+import psycopg2
+
+conn = psycopg2.connect(
+    host="10.1.0.20",
+    port=5433,
+    database="hr_portal",
+    user="admin",
+    password="DC1qaz2wsx"
+)
+conn.autocommit = False
+cur = conn.cursor()
+
+try:
+    print("Creating tenant_employees view...")
+
+    # 先刪除舊的視圖 (如果存在)
+    cur.execute("DROP VIEW IF EXISTS tenant_employees CASCADE;")
+
+    # 建立視圖整合兩個表
+    cur.execute("""
+        CREATE VIEW tenant_employees AS
+        SELECT
+            s.id,
+            s.tenant_id,
+            s.seq_no,
+            s.tenant_emp_code AS employee_id,
+            s.tenant_keycloak_user_id AS keycloak_user_id,
+            r.english_name AS username_base,
+            r.legal_name,
+            r.english_name,
+            r.mobile AS phone,
+            r.mobile,
+            s.hire_at AS hire_date,
+            s.employment_status AS status,
+            s.is_active,
+            s.edit_by,
+            s.created_at,
+            s.updated_at
+        FROM tenant_emp_settings s
+        INNER JOIN tenant_emp_resumes r ON s.tenant_resume_id = r.id;
+    """)
+
+    conn.commit()
+    print("SUCCESS: tenant_employees view created")
+
+    # 驗證視圖
+    cur.execute("""
+        SELECT column_name, data_type
+        FROM information_schema.columns
+        WHERE table_name = 'tenant_employees'
+        ORDER BY ordinal_position;
+    """)
+
+    columns = cur.fetchall()
+    print("\nView structure:")
+    for col in columns:
+        print(f"  {col[0]:<25} {col[1]}")
+
+    # 測試查詢
+    cur.execute("SELECT COUNT(*) FROM tenant_employees;")
+    count = cur.fetchone()[0]
+    print(f"\nTotal employees: {count}")
+
+    if count > 0:
+        cur.execute("SELECT employee_id, legal_name, english_name, status FROM tenant_employees LIMIT 3;")
+        employees = cur.fetchall()
+        print("\nSample data:")
+        for emp in employees:
+            print(f"  {emp[0]:<15} {emp[1]:<20} {emp[2]:<20} {emp[3]}")
+
+except Exception as e:
+    conn.rollback()
+    print(f"ERROR: {e}")
+    import traceback
+    traceback.print_exc()
+finally:
+    cur.close()
+    conn.close()