fix: pass device as string (Hydra/OmegaConf rejects torch.device)

server.py

@@ -45,7 +45,9 @@ def _load_model():
     print("[server] loading Kimodo-SOMA-RP-v1.1 ...", file=sys.stderr, flush=True)
     from kimodo import load_model
 
-    _device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+    # Must be a string (kimodo passes this through Hydra/OmegaConf which
+    # rejects non-primitive types like torch.device).
+    _device = "cuda:0" if torch.cuda.is_available() else "cpu"
     print(f"[server] device = {_device}", file=sys.stderr, flush=True)
 
     model, resolved = load_model(