FromSettings now returns llm.NewRetrying around the configured adapter,
so every Provider it builds retries transient Generate failures and gets
the default timeout; ListModels and Verify pass through.
The test recording transport now answers 400 instead of failing the
round trip: the ollama adapter reports a transport failure as
ErrTimeout, which is retried, so the helper would see three requests.
Tests: a 429 then 200 succeeds on the second request; exhausted retries
return ErrProvider after MaxRetries+1 requests with no key in any error.
Maestro task: 1a882923-fdb4-4576-ab82-9529e9974b26
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>