dig-events-protocol 0.1.3

Canonical DIG Network blockchain→app event contract: the wallet/chain event taxonomy (WalletEvent, EventKind, Cursor, EmittedEvent, SyncStatus) plus the EventEmitter/CatchUp shape traits that the node engine emits and apps subscribe to — a pure leaf crate (serde + enumset + async-trait, no dig-* deps) that freezes the event wire format against drift.