refactor(player): move TimestampLabel from PlayerTransportZone to PlayerSeekZone so volume centers against buttons row height

DeepDrftPublic.Client/Controls/AudioPlayerBar/PlayerTransportZone.razor.css

@@ -2,13 +2,3 @@
 .transport-zone {
     min-width: 180px;
 }
-
-/* Narrow (< 600px): lay the transport root horizontally (controls beside
-   timestamp) so it fits on one line next to VolumeControls. Scoped to the
-   root .transport-zone stack so the nested controls stack is untouched. */
-@media (max-width: 599.98px) {
-    .transport-zone {
-        flex-direction: row !important;
-        align-items: center;
-    }
-}