Fix autoplay countdown showing in repeat one queue mode

When queue mode was set to repeat one, the "Playing in N seconds"
countdown still appeared after a video ended, showing the next queued
video - then restarting the current one anyway. The video-end path
never consulted the queue mode; only playNext() did, after the
countdown had already run.

- PlayerService.backendDidFinishPlaying: restart immediately in repeat
  one mode, regardless of queue contents, player visibility, background,
  or PiP. This also fixes repeat one never looping with an empty queue.
- ExpandedPlayerSheet.isAutoPlayEnabled: false in repeat one mode, which
  gates all countdown triggers (start on ended, overlay render, re-arm
  on appear) on iOS/macOS.
- TVPlayerView.handleVideoEnded: early-return in repeat one mode so
  tvOS shows neither the countdown nor the replay controls.

Yattee/Views/Player/ExpandedPlayerSheet.swift

@@ -134,7 +134,8 @@ struct ExpandedPlayerSheet: View {
 
     var isAutoPlayEnabled: Bool {
         (appEnvironment?.settingsManager.queueEnabled ?? true) &&
-        (appEnvironment?.settingsManager.queueAutoPlayNext ?? true)
+        (appEnvironment?.settingsManager.queueAutoPlayNext ?? true) &&
+        playerState?.queueMode != .repeatOne
     }
 
     var autoPlayCountdownDuration: Int {