Multi-Screen Sync for BrightSign Video Walls

Introduces synchronized playback across BrightSign player groups, enabling video wall configurations where each screen plays distinct but time-aligned content.

Sync is configured at the Player Group level. When all players in a group are BrightSign devices, operators can designate a leader, assign screen positions, and save — the system generates and pushes per-player sync configuration automatically. Groups can include 2 or more players, with each player mapped to a screen position and a shared sync domain.