s&box networking: Choosing the right [Sync] flags — FromHost, Query, Interpolate

In s&box multiplayer, developers are unsure which [Sync] flags to use and when. Using [Sync] alone replicates from owner to all clients, but host-authoritative values (health, score, game state) need SyncFlags.FromHost. Computed properties that change without a setter being called need SyncFlags.Query. Without the right flags, values either don't replicate or replicate from the wrong authority.