Add experimental MLX backend and engine with imagegen support (#13648)

* WIP - MLX backend with gemma3

* MLX: add cmake and go tag build toggles

To build the new MLX backend code:
  cmake --preset MLX
  cmake --build --preset MLX --parallel
  cmake --install build --component MLX
  go build -tags mlx .

Note: the main.go entrypoint for the MLX engine will change in a follow up commit.

* add experimental image generation runtime

* add experimental image generation runtime

* MLX: wire up cuda build for linux

* MLX: get dependencies correct and dedup

This is still too large for a unified github artifact, but is now "correct" for the mlx_cuda_v13
directory.

* fix relative link bug in dedup

* Add darwin build and readme

* add go build tag for mlx dependent code and wire up build_darwin.sh

* lint cleanup

* macos: build mlx for x86

This will be CPU only.

* cuda build instructions and fix drift from mlx bump

* stale comment

* Delete agent helper doc

* Clean up readme.md

* Revise README for tokenizer clarity and details

Updated README to clarify tokenizer functionality and removed correctness section.

---------

Co-authored-by: jmorganca <jmorganca@gmail.com>

parser/parser_test.go

@@ -21,6 +21,7 @@ import (
 	"golang.org/x/text/encoding/unicode"
 
 	"github.com/ollama/ollama/api"
+	"github.com/ollama/ollama/convert"
 	"github.com/ollama/ollama/fs/ggml"
 )
 
@@ -801,7 +802,7 @@ func createBinFile(t *testing.T, kv map[string]any, ti []*ggml.Tensor) (string,
 	}
 	defer f.Close()
 
-	base := map[string]any{"general.architecture": "test"}
+	var base convert.KV = map[string]any{"general.architecture": "test"}
 	maps.Copy(base, kv)
 
 	if err := ggml.WriteGGUF(f, base, ti); err != nil {