fix(providers): strip reasoning_effort/reasoning from grok-cli requests (#6288)

[diegosouzapw]

Closes #6288

Root cause

open-sse/executors/grok-cli.ts::transformRequest() strips a fixed UNSUPPORTED list of sampling params (presencePenalty, frequencyPenalty, logprobs, topLogprobs — added for #5273) before forwarding the request body to Grok Build's upstream chat-proxy endpoint (https://cli-chat-proxy.grok.com/v1/chat/completions). It never stripped reasoning_effort or a nested reasoning object. Claude Code (routing the Opus slot) sends reasoning_effort on every request, so every grok-build request 400s upstream. The sibling open-sse/executors/xai.ts already solves this class of problem for the separate xai provider — grok-cli is a different executor and was missing the same guard.

Fix

Added "reasoning_effort" and "reasoning" to the UNSUPPORTED strip list in grok-cli.ts::transformRequest().

TDD evidence (Hard Rule #18)

New file tests/unit/grok-cli-reasoning-strip-6288.test.ts:

• RED before the fix: reasoning key assertion failed (true !== false — key was present) and the combined-params test failed on reasoning_effort must be stripped.
• GREEN after the fix: all 3 new tests pass, plus the existing tests/unit/grok-cli-strip-params.test.ts (fix(grok-cli): strip unsupported params (presencePenalty, etc.) before sending #5273) still passes (2/2) — no regression in the original stripping behavior.
• Combined run: node --import tsx/esm --test tests/unit/grok-cli*.test.ts → 20/20 pass.

Gates run green

• file-size (check-file-size.mjs) — no flag on grok-cli.ts or the new test file
• complexity (check-complexity.mjs) — no flag
• typecheck (npm run typecheck:core) — exit 0
• lint (eslint --suppressions-location config/quality/eslint-suppressions.json) — exit 0 on both changed files
• test — new regression file + existing sibling grok-cli-strip-params.test.ts, 20/20 pass

[gemini-code-assist]

Warning

You have reached your daily quota limit. Please wait up to 24 hours and I will start processing your requests again!

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.

[diegosouzapw]

Merged — synced onto the v3.8.47 tip (CONFLICTING was base-drift). CHANGELOG guard applied. All checks green. Fixes #6288.