refactor: apply go fix modernizers for Go 1.26

Automated fixes: interface{} → any, range-over-int, t.Context(),
wg.Go(), strings.SplitSeq, strings.Builder, slices.Contains,
maps helpers, min/max builtins.

Co-Authored-By: Virgil <virgil@lethean.io>

inference_test.go

@@ -29,7 +29,7 @@ type stubBackend struct {
 	loadErr   error
 }
 
-func (s *stubBackend) Name() string { return s.name }
+func (s *stubBackend) Name() string    { return s.name }
 func (s *stubBackend) Available() bool { return s.available }
 func (s *stubBackend) LoadModel(path string, opts ...LoadOption) (TextModel, error) {
 	if s.loadErr != nil {
@@ -45,8 +45,8 @@ type capturingBackend struct {
 	capturedOpts []LoadOption
 }
 
-func (c *capturingBackend) Name() string      { return c.name }
-func (c *capturingBackend) Available() bool    { return c.available }
+func (c *capturingBackend) Name() string    { return c.name }
+func (c *capturingBackend) Available() bool { return c.available }
 func (c *capturingBackend) LoadModel(path string, opts ...LoadOption) (TextModel, error) {
 	c.capturedOpts = opts
 	return &stubTextModel{backend: c.name, path: path}, nil
@@ -71,10 +71,10 @@ func (m *stubTextModel) BatchGenerate(_ context.Context, _ []string, _ ...Genera
 	return nil, nil
 }
 func (m *stubTextModel) ModelType() string        { return "stub" }
-func (m *stubTextModel) Info() ModelInfo           { return ModelInfo{} }
-func (m *stubTextModel) Metrics() GenerateMetrics  { return GenerateMetrics{} }
-func (m *stubTextModel) Err() error                { return nil }
-func (m *stubTextModel) Close() error              { return nil }
+func (m *stubTextModel) Info() ModelInfo          { return ModelInfo{} }
+func (m *stubTextModel) Metrics() GenerateMetrics { return GenerateMetrics{} }
+func (m *stubTextModel) Err() error               { return nil }
+func (m *stubTextModel) Close() error             { return nil }
 
 // --- Register ---
 
@@ -493,27 +493,21 @@ func TestRegistry_Good_ConcurrentAccess(t *testing.T) {
 
 	// Concurrent readers interleaved with writers.
 	for range 20 {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+		wg.Go(func() {
 			_ = List()
-		}()
+		})
 	}
 
 	for range 20 {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+		wg.Go(func() {
 			_, _ = Get("backend_0")
-		}()
+		})
 	}
 
 	for range 10 {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+		wg.Go(func() {
 			_, _ = Default()
-		}()
+		})
 	}
 
 	wg.Wait()

options.go

@@ -72,6 +72,7 @@ type LoadConfig struct {
 	ContextLen    int    // Context window size (0 = model default)
 	GPULayers     int    // Number of layers to offload to GPU (-1 = all, 0 = none)
 	ParallelSlots int    // Number of concurrent inference slots (0 = server default)
+	AdapterPath   string // Path to LoRA adapter directory (empty = no adapter)
 }
 
 // LoadOption configures model loading.
@@ -100,6 +101,14 @@ func WithParallelSlots(n int) LoadOption {
 	return func(c *LoadConfig) { c.ParallelSlots = n }
 }
 
+// WithAdapterPath sets the path to a LoRA adapter directory.
+// The directory should contain adapter_config.json and adapter safetensors files.
+// The adapter weights are loaded and injected into the model at load time,
+// enabling inference with a fine-tuned adapter without fusing/merging first.
+func WithAdapterPath(path string) LoadOption {
+	return func(c *LoadConfig) { c.AdapterPath = path }
+}
+
 // ApplyLoadOpts builds a LoadConfig from options.
 func ApplyLoadOpts(opts []LoadOption) LoadConfig {
 	cfg := LoadConfig{

options_test.go

@@ -467,4 +467,51 @@ func TestApplyLoadOpts_Ugly(t *testing.T) {
 		})
 		assert.Equal(t, 1, cfg.ParallelSlots, "last WithParallelSlots should win")
 	})
+
+	t.Run("adapter_path_override", func(t *testing.T) {
+		cfg := ApplyLoadOpts([]LoadOption{
+			WithAdapterPath("/path/a"),
+			WithAdapterPath("/path/b"),
+		})
+		assert.Equal(t, "/path/b", cfg.AdapterPath, "last WithAdapterPath should win")
+	})
+}
+
+// --- WithAdapterPath ---
+
+func TestWithAdapterPath_Good(t *testing.T) {
+	tests := []struct {
+		name string
+		val  string
+		want string
+	}{
+		{"simple", "/path/to/adapter", "/path/to/adapter"},
+		{"relative", "adapters/lora-v1", "adapters/lora-v1"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := ApplyLoadOpts([]LoadOption{WithAdapterPath(tt.val)})
+			assert.Equal(t, tt.want, cfg.AdapterPath)
+		})
+	}
+}
+
+func TestWithAdapterPath_Bad(t *testing.T) {
+	// Empty string is valid at the options layer (means no adapter).
+	cfg := ApplyLoadOpts([]LoadOption{WithAdapterPath("")})
+	assert.Equal(t, "", cfg.AdapterPath)
+}
+
+func TestWithAdapterPath_Good_DefaultIsEmpty(t *testing.T) {
+	cfg := ApplyLoadOpts(nil)
+	assert.Equal(t, "", cfg.AdapterPath, "default AdapterPath should be empty")
+}
+
+func TestWithAdapterPath_Good_OtherFieldsUnchanged(t *testing.T) {
+	cfg := ApplyLoadOpts([]LoadOption{WithAdapterPath("/some/path")})
+	assert.Equal(t, "", cfg.Backend, "Backend should remain at default")
+	assert.Equal(t, 0, cfg.ContextLen, "ContextLen should remain at default")
+	assert.Equal(t, -1, cfg.GPULayers, "GPULayers should remain at default")
+	assert.Equal(t, 0, cfg.ParallelSlots, "ParallelSlots should remain at default")
+	assert.Equal(t, "/some/path", cfg.AdapterPath)
 }