[Feature] Add Speaker Mode #1
Description
Add a Speaker Mode so presenters can control slides, view notes, and track time while the presentation runs in another tab.
- Add button to open presentation in a new tab.
- Control slides (next / prev) and sync both tabs.
- Show a timer with start, pause, reset.
- Display private speaker notes per slide.
- Keep slides synced even after refresh.
Sync slides via
BroadcastChannelor etc.