Add the Config view: edit and save the settings, applied without a restart

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/ui/cover_test.go

@@ -7,6 +7,7 @@ import (
 	"image/color"
 	"image/jpeg"
 	"image/png"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -158,11 +159,11 @@ func TestCoverViewDraws(t *testing.T) {
 
 func TestLoadCoverCachesAndDedupes(t *testing.T) {
 	a := newTestApp(t)
-	fetches := 0
+	var fetches atomic.Int32
 	var buf bytes.Buffer
 	png.Encode(&buf, stripes(10, 20))
 	ref := coverRef{key: "k", fetch: func(context.Context) ([]byte, error) {
-		fetches++
+		fetches.Add(1)
 		return buf.Bytes(), nil
 	}}
 
@@ -173,8 +174,8 @@ func TestLoadCoverCachesAndDedupes(t *testing.T) {
 	if len(a.coverCache.waiting["k"]) != 2 {
 		t.Fatalf("waiters = %d, want 2", len(a.coverCache.waiting["k"]))
 	}
-	if fetches > 1 {
-		t.Errorf("fetched %d times", fetches)
+	if n := fetches.Load(); n > 1 {
+		t.Errorf("fetched %d times", n)
 	}
 }