ggml: Multiply by numParallel for gptoss sliding window

When computing the graph size estimate, the context size is already
multiplied by numParallel so estimates reflect that. However, since
sliding window models use a smaller, fixed context size, they need
to manually take numParallel into account.

fs/ggml/ggml.go

@@ -670,7 +670,7 @@ func (f GGML) GraphSize(context, batch uint64, numParallel int, kvCacheType stri
 		for i := range kv {
 			kv[i] = uint64(float64((embeddingHeadsK+embeddingHeadsV)*headsKV) * bytesPerElement)
 			if i%2 == 0 {
-				kv[i] *= (4096 + batch)
+				kv[i] *= (uint64(numParallel)*4096 + batch)
 			} else {
 				kv[i] *= context
 			}