Speed up wallet synchronization, especially re-syncs of large wallets:
- Incremental address discovery: known indices from the previous sync
(NextReceiveIndex/NextChangeIndex) are fetched in a single parallel
burst instead of sequential gap-limit rounds, cutting round-trips from
O(used/gapLimit) to ~O(1). Receive and change chains scan in parallel.
- Merge tx download and Merkle verification into one parallel phase
(no barrier between them); the per-call semaphore is dropped in favor
of the transport-level in-flight gate.
- Persist verified block headers (SyncCache.BlockHeaders, height -> hex):
immutable once stored, so blockchain.block.header round-trips for
already-verified proofs are eliminated on later syncs.
- RetryOnBusyAsync with exponential backoff around server calls, treating
-101/-102 and "server busy"/"excessive resource usage" as transient.
Wire the new PreloadCaches/ExportCaches signatures through the desktop
view model and the CLI sync command.
Introduce IWalletAccount interface to abstract HD, imported-xprv, WIF,
and watch-only account types. HdAccount implements the interface; the
new ImportedKeyAccount handles lists of WIF keys with fixed addresses
(no gap scanning, change returns to first address).
WalletLoader gains three factory methods:
- NewFromXpub: watch-only from SLIP-132 xpub/ypub/zpub
- NewFromXprv: spendable from SLIP-132 xprv/yprv/zprv
- NewFromWif: spendable from one or more WIF private keys
WalletDocument gains optional AccountXprv and WifKeys fields; AccountPath
and AccountXpub become nullable (absent for WIF wallets). IsWatchOnly
updated to cover all non-signing wallet kinds.
TransactionFactory and CLI OpenWallet() updated to IWalletAccount.
12 new unit tests in ImportedKeyAccountTests cover factory round-trips,
address derivation, and watch-only detection.
TransactionFactory now selects only confirmed UTXOs (height > 0), so
mempool funds are visible as pending balance but never spendable, with
a clear error when only unconfirmed funds are available. GUI and CLI
labels updated to "in attesa di conferma (non spendibile)".
davide