Go endpoint: kimi-k3 rejects 'n' parameter (400: n: Input should be None)

Bug

The OpenCode Go endpoint (https://opencode.ai/zen/go/v1/chat/completions) returns HTTP 400 for kimi-k3 whenever the request includes the n parameter — even the OpenAI-default n: 1:

{
  "error": {
    "type": "server_error",
    "message": "Error from provider (Console Go): Upstream request failed: n: Input should be None"
  }
}

Reproduction

curl https://opencode.ai/zen/go/v1/chat/completions \
  -H "Authorization: Bearer $OPENCODE_GO_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"kimi-k3","messages":[{"role":"user","content":"Say OK"}],"max_tokens":16,"n":1}'

-> 400 with the error above. The same request without n succeeds.

Scope

• Affects kimi-k3 with any reasoning_effort value (low/medium/high/max) and also with no effort parameter at all.
• Other Go models tested (kimi-k2.6, kimi-k2.7-code, glm-5.3, minimax-m3, mimo-v2.5) accept n: 1 fine — the bug is specific to kimi-k3's upstream validation.

Impact

Any OpenAI-compatible client that always sends n: 1 (VS Code Copilot Chat custom models, several SDKs) cannot use kimi-k3 on the Go plan at all. Presumably the upstream model's pydantic schema declares n: None = None and rejects any provided value instead of ignoring n=1.