fix: use Railway PORT in app startup

Run via main.py and honor Railway PORT env to avoid Procfile env expansion issues.

Author: kodjima33

Procfile

@@ -1,2 +1,2 @@
-web: uvicorn main:app --host 0.0.0.0 --port $PORT
+web: python main.py
 

main.py

@@ -1898,7 +1898,7 @@ def get_mobile_css() -> str:
 
 if __name__ == "__main__":
     import uvicorn
-    port = int(os.getenv("APP_PORT", 8000))
+    port = int(os.getenv("PORT", os.getenv("APP_PORT", 8000)))
     host = os.getenv("APP_HOST", "0.0.0.0")
 
     print("OMI GitHub Issues Integration (Chat Tools)")