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/show_temp_password.py

@@ -0,0 +1,40 @@
+"""
+顯示臨時密碼
+"""
+import psycopg2
+
+conn = psycopg2.connect(
+    host="10.1.0.20",
+    port=5433,
+    database="hr_portal",
+    user="admin",
+    password="DC1qaz2wsx"
+)
+cur = conn.cursor()
+
+# 查詢最新的臨時密碼
+cur.execute("""
+    SELECT id, username, plain_password, password_hash, created_at, is_used
+    FROM temporary_passwords
+    ORDER BY created_at DESC
+    LIMIT 5;
+""")
+
+passwords = cur.fetchall()
+
+print("=== Temporary Passwords ===\n")
+
+if passwords:
+    for pw in passwords:
+        print(f"ID: {pw[0]}")
+        print(f"Username: {pw[1]}")
+        print(f"Plain Password: {pw[2] if pw[2] else '(已清除)'}")
+        print(f"Password Hash: {pw[3][:50]}..." if pw[3] else "None")
+        print(f"Created At: {pw[4]}")
+        print(f"Is Used: {pw[5]}")
+        print("-" * 50)
+else:
+    print("No temporary passwords found")
+
+cur.close()
+conn.close()