Sync waypoints, routes, tracks, and settings across phone, tablet, and desktop.
Per docs/vision/design.md: local-first, sync when connected.
- Sync scope: markers, routes, tracks, vessel profile, settings, chart downloads (metadata only), instrument connection list
- Conflict resolution strategy (last-writer-wins vs CRDTs)
- Offline-first: sync is opportunistic, never blocks UI
- Account/auth model
- End-to-end encryption option
Sync waypoints, routes, tracks, and settings across phone, tablet, and desktop.
Per docs/vision/design.md: local-first, sync when connected.