create: Clean up experimental paths, fix create from existing safetensor model (#14679)

* create:  Clean up experimental paths

This cleans up the experimental features, and adds both unit and integration test coverage to verify no regressions.

* create: preserve config and layer names when creating from safetensors models

When creating a model FROM an existing safetensors model, ModelFormat,
Capabilities, and layer Name fields were lost. ModelFormat stayed empty
because it's only set from GGML layers (which safetensors models lack),
and layer names weren't copied in parseFromModel. This caused derived
models to fail loading ("config.json not found in manifest").

* review comments

cmd/cmd.go

@@ -54,7 +54,6 @@ import (
 	"github.com/ollama/ollama/types/syncmap"
 	"github.com/ollama/ollama/version"
 	xcmd "github.com/ollama/ollama/x/cmd"
-	"github.com/ollama/ollama/x/create"
 	xcreateclient "github.com/ollama/ollama/x/create/client"
 	"github.com/ollama/ollama/x/imagegen"
 )
@@ -164,11 +163,13 @@ func CreateHandler(cmd *cobra.Command, args []string) error {
 	}
 
 	// Check for --experimental flag for safetensors model creation
+	// This gates both safetensors LLM and imagegen model creation
 	experimental, _ := cmd.Flags().GetBool("experimental")
 	if experimental {
 		if !isLocalhost() {
 			return errors.New("remote safetensor model creation not yet supported")
 		}
+
 		// Get Modelfile content - either from -f flag or default to "FROM ."
 		var reader io.Reader
 		filename, err := getModelfileName(cmd)
@@ -211,23 +212,12 @@ func CreateHandler(cmd *cobra.Command, args []string) error {
 		}, p)
 	}
 
+	// Standard Modelfile + API path
 	var reader io.Reader
 
 	filename, err := getModelfileName(cmd)
 	if os.IsNotExist(err) {
 		if filename == "" {
-			// No Modelfile found - check if current directory is an image gen model
-			if create.IsTensorModelDir(".") {
-				if !isLocalhost() {
-					return errors.New("remote safetensor model creation not yet supported")
-				}
-				quantize, _ := cmd.Flags().GetString("quantize")
-				return xcreateclient.CreateModel(xcreateclient.CreateOptions{
-					ModelName: modelName,
-					ModelDir:  ".",
-					Quantize:  quantize,
-				}, p)
-			}
 			reader = strings.NewReader("FROM .\n")
 		} else {
 			return errModelfileNotFound