Add grand total tax to payput totals

[willme-paddle]

Summary

Adds support for the grandTotalTax field on transaction totals, which shows the net tax amount included in the grand total after credits are applied.

This field has been added to:

• totals on transactions
• adjusted_totals on transactions
• payout_totals on transactions

Note: adjusted_payout_totals does not include this field, as verified against the Paddle OpenAPI specification.

Related

• Paddle API Changelog: See the tax amount charged after credits are applied

Changes

Types (API response interfaces)

• ITransactionTotalsResponse - added grand_total_tax
• ITransactionTotalsAdjustedResponse - added grand_total_tax
• ITransactionPayoutTotalsResponse - added grand_total_tax

Entities (SDK classes)

• TransactionTotals - added grandTotalTax property
• TransactionTotalsAdjusted - added grandTotalTax property
• TransactionPayoutTotals - added grandTotalTax property

Notification types/entities

• ITransactionTotalsNotificationResponse - added grand_total_tax
• ITransactionTotalsAdjustedNotificationResponse - added grand_total_tax
• ITransactionPayoutTotalsNotificationResponse - added grand_total_tax
• TransactionTotalsNotification - added grandTotalTax property
• TransactionTotalsAdjustedNotification - added grandTotalTax property
• TransactionPayoutTotalsNotification - added grandTotalTax property

Tests

• Updated transaction mocks with grand_total_tax values

Testing

• npm run build passes
• npm test passes
• npm run prettier passes
• npm run typecheck:tests passes
• Verified against Paddle OpenAPI specification