docs: update README and CHANGELOG for opencodezen gateway

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Sung-Heon

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- **OpenCode Zen gateway support**: set `gateway: "opencodezen"` in `configure()` and provide `OPENCODEZEN_API_KEY` to route all model requests through [OpenCode Zen](https://opencode.ai/docs/ko/zen/) (`https://opencode.ai/zen/v1`), an OpenAI-compatible gateway with 30+ curated models including Claude, Gemini, GPT, Qwen, and more.
+
 ## [1.0.0] - 2026-03-27
 
 ### Added

README.md

@@ -31,9 +31,9 @@ ANTHROPIC_API_KEY=sk-ant-...
 GOOGLE_GENERATIVE_AI_API_KEY=AIza...
 ```
 
-Alternatively, you can use an AI gateway like Vercel AI Gateway or OpenRouter to route requests to multiple providers without managing individual API keys. If you choose this option, set `AI_GATEWAY_API_KEY` (for Vercel) or `OPENROUTER_API_KEY` (for OpenRouter) instead.
+Alternatively, you can use an AI gateway like Vercel AI Gateway, OpenRouter, or OpenCode Zen to route requests to multiple providers without managing individual API keys. If you choose this option, set `AI_GATEWAY_API_KEY` (for Vercel), `OPENROUTER_API_KEY` (for OpenRouter), or `OPENCODEZEN_API_KEY` (for OpenCode Zen) instead.
 
-You can also route requests through Cloudflare AI Gateway for observability, caching, and rate limiting. Unlike Vercel/OpenRouter, Cloudflare is a proxy (not a reseller), so you still need your own `ANTHROPIC_API_KEY` / `GOOGLE_GENERATIVE_AI_API_KEY` alongside `CLOUDFLARE_ACCOUNT_ID` and `CLOUDFLARE_AI_GATEWAY` (and `CLOUDFLARE_AI_GATEWAY_API_KEY` if the gateway has authentication enabled).
+You can also route requests through Cloudflare AI Gateway for observability, caching, and rate limiting. Unlike Vercel/OpenRouter/OpenCode Zen, Cloudflare is a proxy (not a reseller), so you still need your own `ANTHROPIC_API_KEY` / `GOOGLE_GENERATIVE_AI_API_KEY` alongside `CLOUDFLARE_ACCOUNT_ID` and `CLOUDFLARE_AI_GATEWAY` (and `CLOUDFLARE_AI_GATEWAY_API_KEY` if the gateway has authentication enabled).
 
 Set your Playwright project to read `.env` by adding the following to `playwright.config.ts`  (after `import { defineConfig, devices } from '@playwright/test';`):
 
@@ -82,8 +82,9 @@ import { runSteps, configure } from "passmark";
 
 configure({
   ai: {
-    gateway: "vercel" // or "openrouter" or "cloudflare"
-    // Set AI_GATEWAY_API_KEY (Vercel), OPENROUTER_API_KEY (OpenRouter), or
+    gateway: "vercel" // or "openrouter", "opencodezen", or "cloudflare"
+    // Set AI_GATEWAY_API_KEY (Vercel), OPENROUTER_API_KEY (OpenRouter),
+    // OPENCODEZEN_API_KEY (OpenCode Zen), or
     // CLOUDFLARE_ACCOUNT_ID + CLOUDFLARE_AI_GATEWAY (+ CLOUDFLARE_AI_GATEWAY_API_KEY
     // if the gateway is authenticated) in your .env file. Cloudflare also requires
     // the upstream provider keys (ANTHROPIC_API_KEY, GOOGLE_GENERATIVE_AI_API_KEY).
@@ -170,7 +171,7 @@ import { configure } from "passmark";
 
 configure({
   ai: {
-    gateway: "none", // "none" (default), "vercel", "openrouter", or "cloudflare"
+    gateway: "none", // "none" (default), "vercel", "openrouter", "opencodezen", or "cloudflare"
     models: {
       stepExecution: "google/gemini-3-flash",
       utility: "google/gemini-2.5-flash",
@@ -189,6 +190,7 @@ configure({
 | `GOOGLE_GENERATIVE_AI_API_KEY` | Yes | - | Google API key for Gemini models |
 | `AI_GATEWAY_API_KEY` | If gateway=vercel | - | Vercel AI Gateway API key |
 | `OPENROUTER_API_KEY` | If gateway=openrouter | - | OpenRouter API key |
+| `OPENCODEZEN_API_KEY` | If gateway=opencodezen | - | OpenCode Zen API key |
 | `CLOUDFLARE_ACCOUNT_ID` | If gateway=cloudflare | - | Cloudflare account ID that owns the AI Gateway |
 | `CLOUDFLARE_AI_GATEWAY` | If gateway=cloudflare | - | Cloudflare AI Gateway name (slug) |
 | `CLOUDFLARE_AI_GATEWAY_API_KEY` | If gateway=cloudflare and the gateway is authenticated | - | Cloudflare AI Gateway token (sent as `cf-aig-authorization`) |