chore: add support for grok 4.1 fast

[uinstinct]

Description

support for new grok 4.1

resolves CON-4961

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Checklist

• [] I've read the contributing guide
• [] The relevant docs, if any, have been updated or created
• [] The relevant tests, if any, have been updated or created

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---

Summary by cubic

Add support for xAI Grok 4.1 Fast models and update docs to recommend Grok‑4 for chat, resolving CON‑4961. Also adds Grok 4.1 Fast to CometAPI and increases Grok 4 (07‑09) context to 256k.

• New Features
  • xAI provider: add grok-4-1-fast-reasoning, grok-4-1-fast-non-reasoning, and grok-4 (all 256k context).
  • CometAPI: add grok-4-1-fast-reasoning; bump grok-4-0709 context 128k → 256k; update description.
  • Docs: update chat role to recommend Grok‑4 with hub and YAML examples.

^{Written for commit 698fa69. Summary will update automatically on new commits.}

[cubic-dev-ai]

2 issues found across 3 files

Prompt for AI agents (all 2 issues)

Understand the root cause of the following 2 issues and fix them.


<file name="packages/llm-info/src/providers/xAI.ts">

<violation number="1" location="packages/llm-info/src/providers/xAI.ts:58">
`Grok 4.1 Fast Non Reasoning` reuses the reasoning model id, so consumers will never send requests to the non‑reasoning backend. The `model` string in this block should include `-non-reasoning`.</violation>

<violation number="2" location="packages/llm-info/src/providers/xAI.ts:72">
This addition duplicates the existing `grok-4` model entry defined a few lines above, creating two identical configurations for the same model id. Remove the new block or consolidate so each model id appears only once.</violation>
</file>

_{Reply to cubic to teach it or ask questions. Re-run a review with @cubic-dev-ai review this PR}

[cubic-dev-ai]

No issues found across 3 files

[RomneyDa]

See comments, also can we

• add to the add models form in GUI
• add it to recommended agent models i.e. make sure it gets multi edit tool
• add comments about how the model was tested e.g. does it do well in agent mode? both CLI and extensions?
• make sure it's added to auto tool support
• update the docs

[RomneyDa]

it's a specific model

Suggested change

	"Latest Grok model series with improved reasoning and conversational abilities.",
	"Latest Grok model with improved reasoning and conversational abilities.",

[RomneyDa]

Could we skip to grok 4.1 for recommended?