GUI fields now trim leading and trailing whitespace:

cmd/mxl-player/config.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"mxl-player/internal/playback"
+	"strings"
 	"time"
 )
 
@@ -17,6 +18,10 @@ func resolveDomain(shared, override string) string {
 	return shared
 }
 
+func normalizeFeedInput(domain, uuid string) (string, string) {
+	return strings.TrimSpace(domain), strings.TrimSpace(uuid)
+}
+
 func resolveRetryPolicy(
 	cli playback.RetryPolicy,
 	cliMaxAttemptsSet bool,