snapshot method

@override Future<WalletState> snapshot()

The on-resume cold snapshot (spec §3.3): balance, sync status, Tor state, chain tip, balance age, and the monotonic seq. Cheap; safe to call on resume before re-subscribing to the live stream.

Implementation

@override
Future<WalletState> snapshot() async {
  snapshotCount++;
  if (snapshotThrows) throw StateError('fake snapshot failure');
  // ONE source of truth for the current status (#409 R1, arch review). The
  // real core cannot present a split here: `SyncController::status()` and
  // `subscribe()` both read the single `watch::Sender`, so a cold read and
  // the live stream always agree. This fake stored the status twice and
  // `push()` moved only the stream's copy, so a test could observe a
  // stream/cold-read divergence the product structurally cannot produce —
  // the very shape of the defect #409 R1 exists to fix (two stored copies of
  // one fact, one of which nothing drives). Production reads this path:
  // `walletSnapshotProvider` feeds the sync sheet's before-first-emit
  // fallback.
  return WalletState(
    balance: _snapshot.balance,
    syncStatus: _current,
    tor: _snapshot.tor,
    tip: _snapshot.tip,
    lastSynced: _snapshot.lastSynced,
    everSynced: _snapshot.everSynced,
    rescanRebuilding: _snapshot.rescanRebuilding,
    seq: _snapshot.seq,
  );
}