feat: modernise to Go 1.26 — iterators, slices.Sorted, maps.Keys

- List() now returns deterministic alphabetical order via slices.Sorted(maps.Keys())
- Add All() iter.Seq2[string, Backend] for iterator-based registry access
- Use slices.Insert for prepend in Discover
- Use maps.Values in Default() fallback
- Remove redundant sort.Strings in tests (List() is now sorted)

Co-Authored-By: Gemini <noreply@google.com>
Co-Authored-By: Virgil <virgil@lethean.io>

discover.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"os"
 	"path/filepath"
+	"slices"
 )
 
 // DiscoveredModel describes a model directory found by Discover.
@@ -39,7 +40,7 @@ func Discover(baseDir string) ([]DiscoveredModel, error) {
 	// Also check baseDir itself (in case it's a model directory).
 	if m, ok := probeModelDir(baseDir); ok {
 		// Prepend so the base dir appears first.
-		models = append([]DiscoveredModel{m}, models...)
+		models = slices.Insert(models, 0, m)
 	}
 
 	return models, nil

inference.go

@@ -67,6 +67,8 @@ import (
 	"context"
 	"fmt"
 	"iter"
+	"maps"
+	"slices"
 	"sync"
 	"time"
 )
@@ -212,15 +214,24 @@ func Get(name string) (Backend, bool) {
 	return b, ok
 }
 
-// List returns the names of all registered backends.
+// List returns the names of all registered backends in alphabetical order.
 func List() []string {
 	backendsMu.RLock()
 	defer backendsMu.RUnlock()
-	names := make([]string, 0, len(backends))
-	for name := range backends {
-		names = append(names, name)
+	return slices.Sorted(maps.Keys(backends))
+}
+
+// All returns an iterator over all registered backends.
+func All() iter.Seq2[string, Backend] {
+	return func(yield func(string, Backend) bool) {
+		backendsMu.RLock()
+		defer backendsMu.RUnlock()
+		for k, v := range backends {
+			if !yield(k, v) {
+				return
+			}
+		}
 	}
-	return names
 }
 
 // Default returns the first available backend.
@@ -236,7 +247,7 @@ func Default() (Backend, error) {
 		}
 	}
 	// Fall back to any available
-	for _, b := range backends {
+	for b := range maps.Values(backends) {
 		if b.Available() {
 			return b, nil
 		}

inference_test.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"iter"
-	"sort"
 	"sync"
 	"testing"
 
@@ -96,9 +95,7 @@ func TestRegister_Good_Multiple(t *testing.T) {
 	Register(&stubBackend{name: "beta", available: true})
 	Register(&stubBackend{name: "gamma", available: true})
 
-	names := List()
-	sort.Strings(names)
-	assert.Equal(t, []string{"alpha", "beta", "gamma"}, names)
+	assert.Equal(t, []string{"alpha", "beta", "gamma"}, List())
 }
 
 func TestRegister_Ugly_Overwrites(t *testing.T) {
@@ -150,9 +147,7 @@ func TestList_Good_Populated(t *testing.T) {
 	Register(&stubBackend{name: "a", available: true})
 	Register(&stubBackend{name: "b", available: true})
 
-	names := List()
-	sort.Strings(names)
-	assert.Equal(t, []string{"a", "b"}, names)
+	assert.Equal(t, []string{"a", "b"}, List())
 }
 
 // --- Default ---