[feat] GPU 사용 검증 api

Author: hhongyeahh

everTale/app/main.py

@@ -20,3 +20,13 @@
 @app.get("/")
 def root():
     return {"message": "EverTale AI 서버가 정상 실행 중입니다."}
+
+@app.get("/debug/cuda")
+def cuda_health():
+    import torch, os
+    return {
+        "cuda_available": torch.cuda.is_available(),
+        "device_count": torch.cuda.device_count(),
+        "current_device": torch.cuda.current_device() if torch.cuda.is_available() else None,
+        "visible_devices": os.getenv("NVIDIA_VISIBLE_DEVICES", "")
+    }