test: cover transaction revision error from api-specifications#2408

[cursor]

Summary

Adds focused contract coverage confirming that the Node SDK passes the updated transaction_invalid_status_to_revise error code and detail through unchanged, including the server guidance that lists past_due as a revisable transaction status. Bumps the package patch version to 3.8.1 and records the clarification in the changelog.

• Source specification: https://github.com/PaddleHQ/api-specifications/pull/2408
• Linear issue: https://linear.app/paddle/issue/DX-1013/sdk-sync-reflect-past-due-transaction-revision-error-guidance-api

Spec-to-SDK mapping

Specification change	SDK files changed
Runtime error detail now lists billed, past_due, and completed	src/__tests__/internal/base-resource.test.ts — verifies ApiError.code and ApiError.detail pass through unchanged
Patch-level SDK sync metadata	package.json — version 3.8.1; CHANGELOG.md — Unreleased entry

Intentionally excluded

• No production resource, operation, entity, response type, enum, notification, event, or mock changes: the HTTP status, error type, error code, endpoint schema, and webhook surface are unchanged.
• The error title, description, and troubleshooting solution are service-generation/documentation metadata not modeled by this SDK.
• The changelog does not claim that this SDK enabled past_due revisions; it only records the server-guidance clarification and existing generic pass-through behavior.

Validation

• pnpm install --frozen-lockfile — passed
• pnpm build — passed
• pnpm typecheck:tests — passed
• pnpm test --runInBand — passed (34 suites, 276 tests)
• pnpm lint — only the documented generated src/version.ts eol-last exception; pnpm exec eslint ./src --ignore-pattern src/version.ts passed
• pnpm exec prettier --check src/__tests__/internal/base-resource.test.ts — passed

This PR was created by an automated spec-sync agent.