ggml: fix crash for array head counts

If it's an array, it only uses the first value in the array instead of
doing something more intelligent to calculate the estimate

Fixes: #9984

fs/ggml/ggml.go

@@ -53,11 +53,11 @@ func (kv KV) EmbeddingLength() uint64 {
 }
 
 func (kv KV) HeadCount() uint64 {
-	return uint64(kv.Uint("attention.head_count"))
+	return uint64(kv.UintOrFirstArrayValue("attention.head_count"))
 }
 
 func (kv KV) HeadCountKV() uint64 {
-	return uint64(kv.Uint("attention.head_count_kv", 1))
+	return uint64(kv.UintOrFirstArrayValue("attention.head_count_kv", 1))
 }
 
 func (kv KV) EmbeddingHeadCount() uint64 {
@@ -104,6 +104,22 @@ func (kv KV) Bool(key string, defaultValue ...bool) bool {
 	return keyValue(kv, key, append(defaultValue, false)...)
 }
 
+func (kv KV) UintOrFirstArrayValue(key string, defaultValue ...uint32) uint32 {
+	if v, ok := keyValueUntyped(kv, key); ok {
+		if a, ok := v.(*array); ok {
+			signed := a.values[0].(int32)
+			if signed >= 0 {
+				return uint32(signed)
+			}
+			// TODO(drifkin): indicate unexpected data somehow?
+			return defaultValue[0]
+		} else if v, ok := v.(uint32); ok {
+			return v
+		}
+	}
+	return defaultValue[0]
+}
+
 func (kv KV) Strings(key string, defaultValue ...[]string) []string {
 	r := keyValue(kv, key, &array{})
 	s := make([]string, r.size)
@@ -141,11 +157,7 @@ func (kv KV) OllamaEngineRequired() bool {
 }
 
 func keyValue[T string | uint32 | uint64 | float32 | *array | bool](kv KV, key string, defaultValue ...T) T {
-	if !strings.HasPrefix(key, "tokenizer.") && !strings.HasPrefix(key, "general.") {
+	if val, ok := keyValueUntyped(kv, key); ok {
-		key = kv.Architecture() + "." + key
-	}
-
-	if val, ok := kv[key]; ok {
 		return val.(T)
 	}
 
@@ -153,6 +165,18 @@ func keyValue[T string | uint32 | uint64 | float32 | *array | bool](kv KV, key s
 	return defaultValue[0]
 }
 
+func keyValueUntyped(kv KV, key string) (any, bool) {
+	if !strings.HasPrefix(key, "tokenizer.") && !strings.HasPrefix(key, "general.") {
+		key = kv.Architecture() + "." + key
+	}
+
+	if val, ok := kv[key]; ok {
+		return val, true
+	}
+
+	return nil, false
+}
+
 type Tensors struct {
 	items  []*Tensor
 	Offset uint64