core: add DL helper, apply to TrackArt OSD, DankLocationSearch

- unrelated change to add gsettingsOrDconf helpers

core/internal/utils/gsettings.go

@@ -0,0 +1,31 @@
+package utils
+
+import (
+	"fmt"
+	"os/exec"
+	"strings"
+)
+
+func dconfPath(schema, key string) string {
+	return "/" + strings.ReplaceAll(schema, ".", "/") + "/" + key
+}
+
+// GsettingsGet reads a gsettings value, falling back to dconf read.
+func GsettingsGet(schema, key string) (string, error) {
+	if out, err := exec.Command("gsettings", "get", schema, key).Output(); err == nil {
+		return strings.TrimSpace(string(out)), nil
+	}
+	out, err := exec.Command("dconf", "read", dconfPath(schema, key)).Output()
+	if err != nil {
+		return "", fmt.Errorf("gsettings/dconf get failed for %s %s: %w", schema, key, err)
+	}
+	return strings.TrimSpace(string(out)), nil
+}
+
+// GsettingsSet writes a gsettings value, falling back to dconf write.
+func GsettingsSet(schema, key, value string) error {
+	if err := exec.Command("gsettings", "set", schema, key, value).Run(); err == nil {
+		return nil
+	}
+	return exec.Command("dconf", "write", dconfPath(schema, key), "'"+value+"'").Run()
+}