improve: Space hotkey for back audio and consistent button icons

- Add Space key as primary hotkey to play back audio (bg-bg cards only)
  More intuitive than Shift+P for playing the second audio

- Change back audio button icon from MediaSkipNextIcon to MediaPlayIcon
  Both front and back buttons now use the same play icon for consistency

- Update hotkeys help dialog to document Space key
  Mark P/П as legacy (kept for backward compatibility)

This makes the UI more consistent and the Space key is more natural
for playing the back audio without using Shift.

2 files changed, 10 insertions, 4 deletions

diff --git a/internal/gui/app.go b/internal/gui/app.go
index cb0a4fe..03d45aa 100644
--- a/internal/gui/app.go
+++ b/internal/gui/app.go
@@ -1536,8 +1536,9 @@ func (a *Application) onShowHotkeys() {
 **r/р** Regenerate all  
 
 ## Playback
-**p/п** Play audio (front for bg-bg)  
-**P/П** Play back audio (bg-bg only)  
+**p/п** Play front audio (or audio for en-bg)  
+**Space** Play back audio (bg-bg only)  
+**P/П** Legacy: Play back audio (bg-bg only, use Space instead)  
 **u/у** Toggle auto-play  
 
 ## Export & Archive
@@ -2592,11 +2593,16 @@ func (a *Application) handleShortcutKey(key fyne.KeyName) {
 		}
 		a.onNextWord()
 
-	case fyne.KeyP: // Play audio
+	case fyne.KeyP: // Play front audio
 		if a.currentAudioFile != "" {
 			a.audioPlayer.Play()
 		}
 
+	case fyne.KeySpace: // Play back audio (for bg-bg cards)
+		if a.currentAudioFileBack != "" {
+			a.audioPlayer.PlayBack()
+		}
+
 	case fyne.KeyX: // Export to APKG
 		a.onExportToAnki()
 
diff --git a/internal/gui/audio_player.go b/internal/gui/audio_player.go
index f9d0ad7..4846615 100644
--- a/internal/gui/audio_player.go
+++ b/internal/gui/audio_player.go
@@ -51,7 +51,7 @@ func NewAudioPlayer() *AudioPlayer {
 	p.playButtonLabel.TextStyle = fyne.TextStyle{Bold: true}
 
 	p.playBackButton = ttwidget.NewButton("", p.onPlayBack)
-	p.playBackButton.Icon = theme.MediaSkipNextIcon()
+	p.playBackButton.Icon = theme.MediaPlayIcon() // Same icon as front button
 	
 	p.playBackLabel = widget.NewLabel("")
 	p.playBackLabel.TextStyle = fyne.TextStyle{Bold: true}