Multi-photographer presence

While you have an album selected, SnapFlow Sync heartbeats every 30 seconds to Redis to register your presence. When another teammate is in the same album, their email appears as a chip in the hero with a fresh-state ring (emerald = active within the last 45s; amber = older).

This is a viewer presence, not a lock. Two photographers can edit the same album simultaneously — the Activity tab records both. Coordinate via Slack / DM if you need exclusive access.