Add optional recovery-wallet file purge to Settings wipe-data flow

[Copilot]

The Settings wipe-data dialog now supports explicitly removing recovery wallet artifacts, not just app data/wallet records. A new opt-in checkbox allows users to delete encrypted wallet backups and remove the wallet storage file during wipe.

• UI: Wipe Data modal

  • Added Delete recovery wallet files checkbox in the wipe confirmation modal.
  • Added explanatory text: This will delete the encrypted wallet backups from the system.
  • Bound checkbox state to a new DeleteRecoveryWalletFiles ViewModel property.

• Wipe flow behavior

  • OpenWipeDataModal / CloseWipeDataModal now reset the new checkbox state.
  • ConfirmWipeData keeps existing wipe behavior, and conditionally executes recovery-file purge when the checkbox is selected.
  • If recovery-file deletion fails, wipe flow surfaces an explicit failure toast and exits early.

• SDK support for recovery-file deletion

  • Extended wallet app service with DeleteRecoveryWalletFilesAsync(bool deleteWalletFile).
  • Implemented purge logic in WalletAppService:
    • Clears in-memory sensitive wallet cache.
    • Removes secure key entries for stored wallet IDs.
    • Delegates wallet backup cleanup to wallet store.
  • Extended IWalletStore/WalletStore with ClearAll(bool deleteWalletFile):
    • false => empty wallets.json contents.
    • true => delete wallets.json file.
  • Extended IStore with Delete(string key) and implemented in FileStore/InMemoryStore.

if (DeleteRecoveryWalletFiles)
{
    var deleteRecoveryWalletFilesResult =
        await _walletAppService.DeleteRecoveryWalletFilesAsync(deleteWalletFile: true);
    if (deleteRecoveryWalletFilesResult.IsFailure)
    {
        ToastRequested?.Invoke("Wipe data failed while deleting encrypted wallet backups. Please try again.");
        return;
    }
}