The model ID `claude-haiku-3-5` does not exist on Anthropic's API and returns HTTP 404. The correct model is `claude-haiku-4-5` (Claude Haiku 4.5). Fixes both `_PROVIDER_MODELS` and `_FALLBACK_MODELS` lists. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>