fix: 支持从独立环境变量配置 PostgreSQL 数据库

- 添加 DB_ENGINE, DB_NAME, DB_USER 等环境变量
- 支持 PostgreSQL 和 SQLite 切换
- 云服务器默认使用 PostgreSQL

city-manual/scripts/deploy-via-rsync.sh

@@ -77,7 +77,7 @@ python manage.py migrate --noinput
 python manage.py collectstatic --noinput
 
 echo "⚙️  创建 Gunicorn 服务..."
-sudo cat > /etc/systemd/system/city-manual.service << 'EOF'
+sudo bash -c 'cat > /etc/systemd/system/city-manual.service << EOF
 [Unit]
 Description=City Manual Gunicorn Service
 After=network.target
@@ -86,23 +86,19 @@ After=network.target
 User=ubuntu
 Group=ubuntu
 WorkingDirectory=/home/ubuntu/city-manual/backend
-ExecStart=/home/ubuntu/city-manual/backend/venv/bin/gunicorn \
-    --access-logfile - \
-    --workers 3 \
-    --bind unix:/run/city-manual.sock \
-    city_manual.wsgi:application
+ExecStart=/home/ubuntu/city-manual/backend/venv/bin/gunicorn --access-logfile - --workers 3 --bind unix:/run/city-manual.sock city_manual.wsgi:application
 Restart=always
 
 [Install]
 WantedBy=multi-user.target
-EOF
+EOF'
 
 sudo systemctl daemon-reload
 sudo systemctl enable city-manual
 sudo systemctl start city-manual
 
 echo "🌐 配置 Nginx..."
-sudo cat > /etc/nginx/sites-available/city-manual << 'EOF'
+sudo bash -c 'cat > /etc/nginx/sites-available/city-manual << "EOF"
 server {
     listen 80;
     server_name cssc.datalibstar.com;
@@ -124,15 +120,15 @@ server {
     location / {
         include proxy_params;
         proxy_pass http://unix:/run/city-manual.sock;
-        proxy_set_header Host $host;
-        proxy_set_header X-Real-IP $remote_addr;
-        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header Host \$host;
+        proxy_set_header X-Real-IP \$remote_addr;
+        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto \$scheme;
     }
 
     client_max_body_size 10M;
 }
-EOF
+EOF'
 
 sudo ln -sf /etc/nginx/sites-available/city-manual /etc/nginx/sites-enabled/
 sudo nginx -t