✨ New features

• Upsert support for /create-user
  The endpoint now uses upsert logic based on the candidate’s email address. If a candidate already exists, the record is updated instead of creating a duplicate.

🛠 Fixes

• Improved error responses
  Error and validation responses are more consistent and provide clearer, more actionable feedback.

🧹 Chore

• Improved documentation
  Expanded and clarified API documentation, including schema usage, authentication, and integration guidance.

• Versioned base URL introduced
  The API is now available at:
  https://onderwijsregio.onderwijsin.nl/api/v1
  The previous base URL (/api) will remain functional for the foreseeable future, but will be deprecated after the release of v2.