Align backend startup port to environment configuration

backend/app/main.py

@@ -240,8 +240,9 @@ async def startup_event():
             print_route(r)
     except Exception as e:
         robust_print(f"[ROUTES] debug failed: {e}")
+    port = int(os.environ.get("PORT", os.environ.get("API_PORT", "7860")))
     robust_print("-" * 50, flush=True)
-    robust_print("FakeShield API is now ONLINE and listening on port 8001.", flush=True)
+    robust_print(f"FakeShield API is now ONLINE and listening on port {port}.", flush=True)
     robust_print("-" * 50, flush=True)
 
 @app.get("/")
@@ -255,5 +256,6 @@ def root():
 
 if __name__ == "__main__":
     import uvicorn
-    uvicorn.run(app, host="0.0.0.0", port=8001)
+    port = int(os.environ.get("PORT", os.environ.get("API_PORT", "7860")))
+    uvicorn.run(app, host="0.0.0.0", port=port)