feat: export error types from the package root

[buptliuhs]

Summary

Re-export BoxApiError, BoxSdkError, and the RequestInfo / ResponseInfo
types from the package root so consumers can import them directly:

import { BoxApiError } from 'box-node-sdk';

Today the only way to reach BoxApiError is a deep, internal path:

import { BoxApiError } from 'box-node-sdk/lib/box/errors';

Motivation

BoxApiError is the error every consumer needs in order to handle API
failures — it carries the HTTP status, responseInfo, error code, request
id, etc. But it isn't exported from the entry point, so callers must reach
into box-node-sdk/lib/box/errors, an internal lib/ path.

Beyond ergonomics, that deep import can be a hazard when the bare package and
its subpaths are resolved differently by a bundler. For example, if
box-node-sdk is marked external (resolved at runtime) while a deep subpath
import (box-node-sdk/lib/box/errors) is bundled instead, two copies of the
BoxApiError class exist at runtime — the one the SDK throws and the one the
consumer's check references — so error instanceof BoxApiError silently
returns false. Importing from the root, a single specifier, sidesteps that.

Changes

• src/index.ts:

  • export { BoxApiError, BoxSdkError } from './box';
  • export type { RequestInfo, ResponseInfo } from './box';

  (These are already exported from ./box via export * from './errors';
  this just surfaces them at the root.)

Compatibility

Additive, non-breaking — new exports only; no existing signatures change.

Note for maintainers

If src/index.ts is generated by box-codegen rather than hand-maintained,
I'm happy to move this into the generator/templates — please point me at the
right place.

[CLAassistant]

All committers have signed the CLA.