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>

scripts/check-resources.sh

@@ -0,0 +1,68 @@
+#!/bin/bash
+#
+# 檢查系統資源使用狀況
+#
+
+echo "=========================================="
+echo "  System Resource Check"
+echo "=========================================="
+echo ""
+
+# CPU 資訊
+echo "[1/5] CPU Information:"
+lscpu | grep -E "^CPU\(s\)|^Model name|^Thread"
+echo ""
+
+# 記憶體使用
+echo "[2/5] Memory Usage:"
+free -h
+echo ""
+
+# 磁碟使用
+echo "[3/5] Disk Usage:"
+df -h | grep -E "^Filesystem|/$|/data"
+echo ""
+
+# Docker 資源使用
+echo "[4/5] Docker Resource Usage:"
+docker stats --no-stream --format "table {{.Container}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.MemPerc}}"
+echo ""
+
+# PostgreSQL 容器資源
+echo "[5/5] PostgreSQL Containers:"
+docker ps --filter "ancestor=postgres:16-alpine" --format "table {{.Names}}\t{{.Status}}\t{{.Size}}"
+echo ""
+
+echo "=========================================="
+echo "  Resource Summary"
+echo "=========================================="
+echo ""
+
+# 計算 PostgreSQL 容器數量和總記憶體
+PG_COUNT=$(docker ps | grep postgres | wc -l)
+echo "Current PostgreSQL containers: $PG_COUNT"
+echo ""
+
+# 預估資源需求
+echo "Estimated resource requirements:"
+echo ""
+echo "Option A: Shared PostgreSQL (1 container)"
+echo "  ├── CPU: ~2-5%"
+echo "  ├── Memory: ~100-200 MB"
+echo "  └── Disk: ~500 MB"
+echo ""
+echo "Option B: Microservices (3 containers)"
+echo "  ├── CPU: ~6-15%"
+echo "  ├── Memory: ~300-600 MB"
+echo "  └── Disk: ~1.5 GB"
+echo ""
+
+# 系統規格回顧
+echo "Your Ubuntu Server specs:"
+echo "  ├── CPU: 12th Gen Intel Core i5-12400F"
+echo "  ├── RAM: 32 GB"
+echo "  └── Storage: SSD 216GB + HDD 931GB"
+echo ""
+echo "Recommendation: You have MORE than enough resources!"
+echo "                Both options are viable."
+echo ""