Remote managed settings fetch telemetry gains auth diagnostics

The tengu_remote_settings_fetch telemetry event now also records details about authentication, meaning how Claude Code proved who you are when it fetched settings. The new fields are:

• auth_type, token_source and credential_origin (either stored_login or injected_token)
• the outcomes of any token refresh
• retried_after_401, which shows whether the request was retried after the server said it was not authorized
• the server's error type and code, and server_auth_denial
• credential_state, errno and ms_since_startup
• api_key_prefix, sent only when you are signed in with an API key