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/onboard-types.ts

@@ -13,6 +13,7 @@ export type AuthChoice =
   | "openai-codex"
   | "openai-api-key"
   | "openrouter-api-key"
+  | "kilocode-api-key"
   | "litellm-api-key"
   | "ai-gateway-api-key"
   | "cloudflare-ai-gateway-api-key"
@@ -58,6 +59,7 @@ export type AuthChoiceGroupId =
   | "google"
   | "copilot"
   | "openrouter"
+  | "kilocode"
   | "litellm"
   | "ai-gateway"
   | "cloudflare-ai-gateway"
@@ -108,6 +110,7 @@ export type OnboardOptions = {
   openaiApiKey?: string;
   mistralApiKey?: string;
   openrouterApiKey?: string;
+  kilocodeApiKey?: string;
   litellmApiKey?: string;
   aiGatewayApiKey?: string;
   cloudflareAiGatewayAccountId?: string;