Patch Changes 80e1702: feat(xai): support `'none'` and `'medium'` reasoning effort for `grok-4.3`, and curate the model ID autocomplete list `grok-4.3` accepts `reasoning_effort` of `"none" | "low" | "medium" | "high"`, where `"none"` disables reasoning entirely (no thinking tokens) and `"medium"` provides more thinking for less-latency-sensitive applications. Adds `'none'` to the allowed values for `providerOptions.xai.reasoningEffort` on both the chat (`xai()`) and responses (`xai.responses()`) language models. Adds `'medium'` to the chat model's `reasoningEffort` enum (the responses model already supported it).

Top-level `reasoning: 'medium'` now maps to `reasoning_effort: 'medium'` for the chat model (previously it was coerced to `'low'` because `'medium'` was not a valid value). In addition, the `XaiChatModelId` and `XaiResponsesModelId` autocomplete unions have been trimmed to xAI's current model lineup (docs): `grok-4.20-non-reasoning` `grok-4.20-reasoning` `grok-4.3` `grok-latest` Older entries (`grok-3*`, `grok-4`, `grok-4-0709`, `grok-4-latest`, `grok-4-1-fast-`, `grok-4-fast-`, `grok-code-fast-1`, and `grok-4.20-multi-agent-0309`) have been removed from the…