feat: Add Kilo Gateway provider (#20212)

* feat: Add Kilo Gateway provider

Add support for Kilo Gateway as a model provider, similar to OpenRouter.
Kilo Gateway provides a unified API that routes requests to many models
behind a single endpoint and API key.

Changes:
- Add kilocode provider option to auth-choice and onboarding flows
- Add KILOCODE_API_KEY environment variable support
- Add kilocode/ model prefix handling in model-auth and extra-params
- Add provider documentation in docs/providers/kilocode.md
- Update model-providers.md with Kilo Gateway section
- Add design doc for the integration

* kilocode: add provider tests and normalize onboard auth-choice registration

* kilocode: register in resolveImplicitProviders so models appear in provider filter

* kilocode: update base URL from /api/openrouter/ to /api/gateway/

* docs: fix formatting in kilocode docs

* fix: address PR review — remove kilocode from cacheRetention, fix stale model refs and CLI name in docs, fix TS2742

* docs: fix stale refs in design doc — Moltbot to OpenClaw, MoltbotConfig to OpenClawConfig, remove extra-params section, fix doc path

* fix: use resolveAgentModelPrimaryValue for AgentModelConfig union type

---------

Co-authored-by: Mark IJbema <mark@kilocode.ai>

src/commands/auth-choice-options.ts

@@ -94,6 +94,12 @@ const AUTH_CHOICE_GROUP_DEFS: {
     hint: "API key",
     choices: ["openrouter-api-key"],
   },
+  {
+    value: "kilocode",
+    label: "Kilo Gateway",
+    hint: "API key (OpenRouter-compatible)",
+    choices: ["kilocode-api-key"],
+  },
   {
     value: "qwen",
     label: "Qwen",
@@ -206,6 +212,7 @@ const BASE_AUTH_CHOICE_OPTIONS: ReadonlyArray<AuthChoiceOption> = [
     label: "Qianfan API key",
   },
   { value: "openrouter-api-key", label: "OpenRouter API key" },
+  { value: "kilocode-api-key", label: "Kilo Gateway API key" },
   {
     value: "litellm-api-key",
     label: "LiteLLM API key",