Use Gunicorn in Procfile for Render, add platform detection

backend/start_alwrity_backend.py

@@ -9,10 +9,17 @@ import os
 import sys
 import json
 import argparse
+import platform
 from pathlib import Path
 from dataclasses import dataclass, asdict
 from typing import Optional
 
+# Detect platform
+IS_WINDOWS = platform.system() == "Windows"
+IS_LINUX = platform.system() == "Linux"
+
+import uvicorn
+
 
 @dataclass
 class BootstrapResult: