syncStatus

Observable wallet-sync status (#235). EVERY heavy sync this wallet runs publishes here — syncDust, the proactive proactiveDustResync, the shielded + dust refresh, and the forceFullSync genesis rebuild — so a background observer (the foreground-service Live-Update notification) can render progress for whichever phase is in flight without driving the sync itself. The in-app WalletSyncIndicator can also collect this instead of the per-call lambda.