For one subspace and path only one entry survives: later timestamp, then greater digest, then longer payload; the loser is dropped.

This is the entire conflict rule, and it needs no coordination.

Two entries, same room, same shelf. Only one can stay.

The one with the later timestamp wins.

Same timestamp? The greater fingerprint wins. Same fingerprint? The longer payload wins.

The loser is dropped. Not kept in a history. Dropped. Willow calls this destructive editing.

The rule needs no server and no conversation. Any two machines with the same two cards pick the same one.

Check yourself. Two entries have the same timestamp. What decides?