fix: cleanup unpaid order transfers from migration

[jvsena42]

Fixes #461

Description

This PR fixes a bug where unpaid/expired Blocktank orders from the RN backup's paidOrders map were imported as pending transfers during migration, permanently locking funds in balanceInTransferToSpending.

The RN app could store orders in paidOrders even when the payment was never completed. The migration code blindly trusted this map and only filtered out .executed orders, allowing expired/unpaid orders through.

Changes:

1. Only create migration transfers for orders in .paid state (not just skipping .executed)
2. Fix amountSats to use clientBalanceSat instead of clientBalanceSat + feeSat, matching the normal transfer creation flow
3. Handle expired orders in syncTransferStates so any invalid transfers get cleaned up during normal sync
4. Add a one-time cleanup that fetches order states from Blocktank and settles transfers for non-paid orders

Linked Issues/Tasks

• Fixes ios: savings empty and transfer in progress after update #461

Screenshot / Video

simulate-migration.mp4

after-fix.mp4

QA Notes:

To reproduce:

1. On RN app, replace blocktank.ts with this file blocktank.ts to create an order without broadcast the payment
2. Also comment out checkForAppUpdate(); to don't display the update sheet
3. Migrate to native on master branch
4. Expected: Transfer banner never dismissed and amount + fee count on total balance
5. checkout to fix/unpaid-order-import
6. Expected: cleanup invalid transfer and update total balance ✅

[jvsena42]

From the logs, there is no on-chain balance. The mismatch from total comes from the invalid pending transfer