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/run-fix-postgres.ps1

@@ -0,0 +1,103 @@
+# Execute PostgreSQL fix remotely via SSH
+$ErrorActionPreference = "Continue"
+
+Write-Host "========================================" -ForegroundColor Cyan
+Write-Host "  Fixing PostgreSQL Port Configuration" -ForegroundColor Cyan
+Write-Host "========================================" -ForegroundColor Cyan
+Write-Host ""
+
+$REMOTE_HOST = "10.1.0.254"
+$REMOTE_USER = "ubuntu"
+$PASSWORD = "DC1qaz2wsx"
+
+# Create the command as a single string
+$commands = @"
+echo '[1/4] Stopping old PostgreSQL container...'
+docker stop postgres 2>/dev/null
+docker rm postgres 2>/dev/null
+
+echo ''
+echo '[2/4] Starting new container with external access...'
+docker run -d \
+  --name postgres \
+  --restart unless-stopped \
+  -e POSTGRES_PASSWORD="$PASSWORD" \
+  -e TZ=Asia/Taipei \
+  -p 0.0.0.0:5432:5432 \
+  -v postgres-data:/var/lib/postgresql/data \
+  postgres:16
+
+echo ''
+echo '[3/4] Waiting for PostgreSQL...'
+sleep 8
+
+echo ''
+echo '[4/4] Verifying...'
+docker ps | grep postgres
+docker port postgres
+docker exec postgres psql -U hr_user -d hr_portal -c 'SELECT COUNT(*) FROM information_schema.tables WHERE table_schema='\''public'\'' AND table_type='\''BASE TABLE'\'';' 2>/dev/null || echo 'Database check will be done after connection test'
+
+echo ''
+echo '=========================================='
+echo 'PostgreSQL reconfiguration complete!'
+echo '=========================================='
+"@
+
+Write-Host "Connecting to Ubuntu Server..." -ForegroundColor Yellow
+Write-Host ""
+
+# Try using plink if available
+$plinkPath = Get-Command plink -ErrorAction SilentlyContinue
+
+if ($plinkPath) {
+    Write-Host "Using plink for connection..." -ForegroundColor Gray
+    $commands | plink -ssh -batch -pw $PASSWORD "${REMOTE_USER}@${REMOTE_HOST}"
+} else {
+    # Fallback to regular ssh
+    Write-Host "Using ssh for connection..." -ForegroundColor Gray
+    Write-Host "You may need to enter password: $PASSWORD" -ForegroundColor Yellow
+    Write-Host ""
+
+    # Save commands to temp file
+    $tempFile = "$env:TEMP\fix-postgres-commands.sh"
+    $commands | Out-File -FilePath $tempFile -Encoding UTF8
+
+    # Try to execute via ssh with heredoc
+    $sshCommand = "bash -s"
+    Get-Content $tempFile | ssh "${REMOTE_USER}@${REMOTE_HOST}" $sshCommand
+}
+
+$exitCode = $LASTEXITCODE
+
+Write-Host ""
+
+if ($exitCode -eq 0) {
+    Write-Host "========================================" -ForegroundColor Green
+    Write-Host "  Success!" -ForegroundColor Green
+    Write-Host "========================================" -ForegroundColor Green
+    Write-Host ""
+    Write-Host "PostgreSQL is now accessible from:" -ForegroundColor White
+    Write-Host "  Host: 10.1.0.254" -ForegroundColor Cyan
+    Write-Host "  Port: 5432" -ForegroundColor Cyan
+    Write-Host ""
+    Write-Host "Testing connection from Windows..." -ForegroundColor Yellow
+    Write-Host ""
+
+    # Test connection
+    Start-Sleep -Seconds 3
+
+    Write-Host "Running database connection test..." -ForegroundColor Yellow
+    cd "W:\DevOps-Workspace\hr-portal\backend"
+    python test_db_connection.py
+
+} else {
+    Write-Host "========================================" -ForegroundColor Red
+    Write-Host "  Error occurred" -ForegroundColor Red
+    Write-Host "========================================" -ForegroundColor Red
+    Write-Host ""
+    Write-Host "Exit code: $exitCode" -ForegroundColor Yellow
+    Write-Host ""
+    Write-Host "Please check the output above for errors." -ForegroundColor Yellow
+}
+
+Write-Host ""