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/tvOS/TVPlayerView.swift

@@ -1046,6 +1046,11 @@ struct TVPlayerView: View {
             controlsVisible = false
         }
 
+        // Repeat one: PlayerService restarts the video itself - no countdown, no replay controls
+        if playerState?.queueMode == .repeatOne {
+            return
+        }
+
         // Check if autoplay is enabled and there's a next video
         let autoPlayEnabled = appEnvironment?.settingsManager.queueAutoPlayNext ?? true
         let hasNextVideo = playerState?.hasNext ?? false