Documentation: getting started guide has outdated examples

The getting started guide references API v1 endpoints that have been deprecated. New users are hitting 404s on their first try.

Specifically:
- The auth example uses the old token format
- The webhook setup section references a removed endpoint

Would be happy to submit a docs PR with updated examples.

Locate the getting started guide and review its auth example and webhook setup section first. Compare the API v1 references with the current token format and supported webhook endpoint, then update the examples so new users no longer encounter deprecated references or 404s.

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