forceResyncBalance

Deliberate "Re-sync balance" recovery: rebuild the unshielded UTXO cache from genesis to fix a stale NIGHT count (ghost AVAILABLE coins left by a missed spent-event / cross-app spend on the shared wallet, roadmap #52). Reuses lastRequestedConfig — the config the user last acted on — so the Settings affordance can fire this without re-threading the config through the overlay. No-op if no wallet action has run yet (nothing to resync, and no config to bootstrap with).

Delegates to refreshBalance with resyncUnshielded = true, so the existing busy state + syncProgress indicator cover the rebuild and the live observer shows the count self-correct.