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/app/models/emp_personal_service_setting.py

@@ -0,0 +1,50 @@
+"""
+員工個人化服務設定 Model
+記錄員工啟用的個人化服務（SSO, Email, Calendar, Drive, Office）
+"""
+from datetime import datetime
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, ForeignKey, UniqueConstraint, Index
+from sqlalchemy.orm import relationship
+
+from app.db.base import Base
+
+
+class EmpPersonalServiceSetting(Base):
+    """員工個人化服務設定表"""
+
+    __tablename__ = "tenant_emp_personal_service_settings"
+    __table_args__ = (
+        UniqueConstraint("tenant_id", "keycloak_user_id", "service_id", name="uq_emp_service"),
+        Index("idx_emp_service_tenant", "tenant_id"),
+        Index("idx_emp_service_user", "keycloak_user_id"),
+        Index("idx_emp_service_service", "service_id"),
+    )
+
+    id = Column(Integer, primary_key=True, index=True)
+    tenant_id = Column(Integer, ForeignKey("tenants.id", ondelete="CASCADE"), nullable=False,
+                       comment="租戶 ID")
+    keycloak_user_id = Column(String(36), nullable=False, comment="Keycloak User UUID")
+    service_id = Column(Integer, ForeignKey("personal_services.id", ondelete="CASCADE"), nullable=False,
+                        comment="個人化服務 ID")
+
+    # 服務配額設定（依服務類型不同）
+    quota_gb = Column(Integer, nullable=True, comment="儲存配額 (GB)，適用於 Drive")
+    quota_mb = Column(Integer, nullable=True, comment="郵件配額 (MB)，適用於 Email")
+
+    # 審計欄位（完整記錄）
+    enabled_at = Column(DateTime, default=datetime.utcnow, nullable=False, comment="啟用時間")
+    enabled_by = Column(String(36), nullable=True, comment="啟用者 keycloak_user_id")
+    disabled_at = Column(DateTime, nullable=True, comment="停用時間（軟刪除）")
+    disabled_by = Column(String(36), nullable=True, comment="停用者 keycloak_user_id")
+
+    # 通用欄位
+    is_active = Column(Boolean, default=True, nullable=False, comment="是否啟用")
+    edit_by = Column(String(36), nullable=True, comment="最後編輯者 keycloak_user_id")
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False, comment="建立時間")
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False, comment="更新時間")
+
+    # 關聯
+    service = relationship("PersonalService")
+
+    def __repr__(self):
+        return f"<EmpPersonalServiceSetting user={self.keycloak_user_id} service={self.service_id}>"