On create and edit, a non-empty cf_api_token is checked with Cloudflare (GET /zones): it is saved only when
the token sees exactly one zone and the customer's domain is that zone or a name under it. More zones, another
zone, no zone, or Cloudflare not answering -> the form re-renders with one sentence and nothing is saved (the
previous token stays). An unchanged token on an unchanged domain and an empty token (HTTP-01) make no call.
The token is never logged and never in a sentence or error. Tests use a fake Cloudflare (httptest).
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS