Fix KVCache constructor call — device as keyword arg, not positional

KVCache signature has max_comp before device, so positional pass of dev
was hitting max_comp parameter instead of device.

single_shot_inference.py

@@ -861,7 +861,7 @@ def main():
     n_ih = cfg.get("index_n_heads", 64); ihd = cfg.get("index_head_dim", 128); itk = cfg.get("index_topk", 1024)
     for li in range(n_layers):
         dev = f"cuda:{li % NUM_GPUS}"; ratio = cr[li] if li < len(cr) else 128
-        kv_caches[li] = KVCache(hd, cfg.get("sliding_window", 128), dev)
+        kv_caches[li] = KVCache(hd, cfg.get("sliding_window", 128), device=dev)
         if ratio > 0: compressors[li] = Compressor(ratio, hd, H, dev)
         if ratio == 4: indexers[li] = Indexer(n_ih, ihd, itk, dev)