Smarter Playback Navigation in Outline and Mind Map

🔄 Improvements

• Highlighted playable branches in the mind map during playback (clear visual navigation)
  Screenshot
  You can now instantly see where playback can continue, making it easier to stay oriented in complex maps.

• Highlighted the current header in the outline when the transcript panel is hidden (keep context without opening transcript)
  Demo video
  Even with the transcript closed, the outline clearly shows your current position.

• Auto-scroll to the current phrase during playback (stay focused on active content)
  Demo video
  The outline now follows playback automatically, so the spoken phrase is always visible without manual scrolling.

✨ New Features

• Visual playback markers integrated across mind map and outline
  Playback state is now consistently reflected in both views, improving navigation and context awareness.

🛠 Fixes

• Fixed: duplicate request preparation that could cause unnecessary delays during session initialization

And other improvements