Add Photographer Endpoint

Adds a photographer to a project WITHOUT creating a login account or sending an email. Email is optional and can be filled in later (via editPhotographer) or when the photographer is invited (via invitePhotographer).

Expects: - JSON with: - 'name': photographer's name (required) - 'email': photographer's email (optional) - 'description': photographer's description (optional) - 'projectId': ID of the project to associate with (required)

Returns: - Success message with the new photographer id if successful - Error if required fields are missing or other issues occur