fix: Change baseDir assignment to use ModelPath (#9010)

Fixes: https://github.com/mudler/LocalAI/issues/9005

Signed-off-by: Ettore Di Giacinto <mudler@users.noreply.github.com>

backend/go/acestep-cpp/acestepcpp_test.go

@@ -112,6 +112,7 @@ func TestLoadModel(t *testing.T) {
 	
 	resp, err := client.LoadModel(context.Background(), &pb.ModelOptions{
 		ModelFile: mainModelPath,
+		ModelPath: modelDir,
 		Options: []string{
 			"text_encoder_model:Qwen3-Embedding-0.6B-Q8_0.gguf",
 			"dit_model:acestep-v15-turbo-Q8_0.gguf",
@@ -151,6 +152,7 @@ func TestSoundGeneration(t *testing.T) {
 	// Load models
 	loadResp, err := client.LoadModel(context.Background(), &pb.ModelOptions{
 		ModelFile: mainModelPath,
+		ModelPath: modelDir,
 		Options: []string{
 			"text_encoder_model:Qwen3-Embedding-0.6B-Q8_0.gguf",
 			"dit_model:acestep-v15-turbo-Q8_0.gguf",

backend/go/acestep-cpp/goacestepcpp.go

@@ -24,7 +24,7 @@ func (a *AceStepCpp) Load(opts *pb.ModelOptions) error {
 	lmModel := opts.ModelFile
 
 	// Get the base directory from ModelFile for resolving relative paths
-	baseDir := filepath.Dir(lmModel)
+	baseDir := opts.ModelPath
 
 	var textEncoderModel, ditModel, vaeModel string