Sync ark funds across devices

Ark vtxos lived only in per-device storage, so a second device with the
same seed saw the right on-chain balance (that rides the snapshot) but
none of its ark funds — board/change vtxos exist only where created.
Ark state now rides the encrypted nostr snapshot as a merge-safe cache
extension: additive union (bring in vtxos a device is missing) with
each device's own server reconcile() as the authority for spent-ness,
so a stale or wrong 'spent' on one device can never propagate and
poison the others. A connect-time reconcile catches coins spent
elsewhere while a device was away, and a live subscription to our own
replaceable event merges another device's new coins within seconds.

New seam: registerCacheExtension({mergeAlways:true}) extensions get
fed snapshots that aren't newer than local state too (last-writer-wins
is right for rescannable chain data, wrong for merge-style vtxo state),
and nostr.subscribeStates for the live path.

Verified two same-seed devices over a mini relay: B sees A's boarded
balance with zero mailbox activity, spends a synced vtxo, A converges
to a stable balance with the spent vtxo correctly marked.

Co-Authored-By: Claude Fable 5 <[email protected]>

0 files changed, 0 insertions, 0 deletions