Intra-bank transfer accepts zero and negative amounts #2011

Summary:

Intra-bank transfer confirmation treats zero and negative numeric amounts as valid. The shared validation only checks that the amount is numeric and not greater than the selected balance, so 0 and pasted negative values can pass client-side validation and be used to build a transfer payload.

Steps to reproduce:

1. Open Send Money and proceed to an intra-bank transfer confirmation screen with a selected source account.
2. Enter 0 as the amount, or paste a negative value such as -1.
3. Enter a description.
4. Check the confirm button state or submit the form.

Expected behavior:

The app should require a transfer amount greater than zero and reject zero or negative values before attempting a transfer.

Observed behavior:

TransferConfirmState.amountIsValid returns true for 0 and negative values when they are not greater than the selected balance, and validateTransfer() does not reject non-positive amounts.

Device and Android version:

All supported platforms. This is a shared Kotlin Multiplatform validation issue in the transfer confirmation flow.

Screenshots:

Not applicable.

Possible fixes:

Update the transfer confirmation amount validation to require amount > 0, reset processing state when validation fails, and add regression coverage for non-positive amounts.