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/check_env_config.py

@@ -0,0 +1,56 @@
+"""
+檢查環境配置記錄
+"""
+import psycopg2
+
+conn = psycopg2.connect(
+    host="10.1.0.20",
+    port=5433,
+    database="hr_portal",
+    user="admin",
+    password="DC1qaz2wsx"
+)
+cur = conn.cursor()
+
+# 查詢環境配置
+cur.execute("""
+    SELECT config_category, config_key, is_configured
+    FROM installation_environment_config
+    ORDER BY config_category, config_key;
+""")
+
+configs = cur.fetchall()
+
+print("=== Environment Config ===\n")
+
+if configs:
+    current_category = None
+    for cfg in configs:
+        if cfg[0] != current_category:
+            if current_category is not None:
+                print()
+            print(f"[{cfg[0]}]")
+            current_category = cfg[0]
+
+        status = "OK" if cfg[2] else "NOT CONFIGURED"
+        print(f"  {cfg[1]:<30} [{status}]")
+else:
+    print("No environment config records found")
+
+print("\n=== Required Categories ===")
+required = ["redis", "database", "keycloak"]
+
+cur.execute("""
+    SELECT DISTINCT config_category
+    FROM installation_environment_config
+    WHERE is_configured = TRUE;
+""")
+
+configured = [row[0] for row in cur.fetchall()]
+
+for cat in required:
+    status = "OK" if cat in configured else "MISSING"
+    print(f"  {cat:<15} [{status}]")
+
+cur.close()
+conn.close()