feat(vercel): use -non-reasoning suffix for Grok 4.x when reasoning is disabled

[kilo-code-bot]

Summary

• When a Grok 4.x model (e.g. x-ai/grok-4-fast, x-ai/grok-4.1-fast, x-ai/grok-4.20-beta) is routed to Vercel and reasoning is explicitly disabled, the Vercel model ID now uses the -non-reasoning suffix instead of -reasoning.
• mapModelIdToVercel accepts a new optional reasoningDisabled parameter (defaults to false); when true and the hardcoded Vercel ID ends with -reasoning, the suffix is replaced with -non-reasoning.
• Both call sites in vercel/index.ts (shouldRouteToVercel and applyVercelSettings) pass isReasoningExplicitlyDisabled(request) to keep routing checks and model name in sync.

Verification

• TypeScript environment not fully available locally (missing tsgo/jest binaries); relying on CI.

Visual Changes

N/A

Reviewer Notes

• The change is additive: non-Grok models and Grok models without reasoning disabled are unaffected.
• isReasoningExplicitlyDisabled already handles all three request kinds (chat_completions, messages, responses).

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (2 files)

• apps/web/src/lib/ai-gateway/providers/vercel/index.ts
• apps/web/src/lib/ai-gateway/providers/vercel/mapModelIdToVercel.ts

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_{Reviewed by gpt-5.4-20260305 · 118,833 tokens}