fix(gemini-cua): Update template to use Stagehand v3 API

[cursor]

Problem

The Gemini CUA template is using Stagehand v2 syntax while the package version needs to be v3, causing the template to fail when invoked.

Related Linear issue: KERNEL-716

Solution

1. Update templates/typescript/gemini-cua/package.json:

{
  "name": "ts-gemini-cua",
  "module": "index.ts",
  "type": "module",
  "private": true,
  "peerDependencies": {
    "typescript": "^5"
  },
  "dependencies": {
    "@browserbasehq/stagehand": "^3.0.1",
    "@onkernel/sdk": "^0.18.0",
    "zod": "=3.25.67"
  }
}

2. Update templates/typescript/gemini-cua/index.ts:

Stagehand constructor (v2 → v3):

// Before (v2)
const stagehand = new Stagehand({
  env: "LOCAL",
  verbose: 1,
  domSettleTimeoutMs: 30_000,
  modelName: "gpt-4o",
  modelClientOptions: {
    apiKey: OPENAI_API_KEY
  },
  localBrowserLaunchOptions: {
    cdpUrl: kernelBrowser.cdp_ws_url
  }
});

// After (v3)
const stagehand = new Stagehand({
  env: "LOCAL",
  localBrowserLaunchOptions: {
    cdpUrl: kernelBrowser.cdp_ws_url,
  },
  model: "openai/gpt-4o",
  apiKey: OPENAI_API_KEY,
  verbose: 1,
  domSettleTimeout: 30_000
});

Page access (v2 → v3):

// Before (v2)
const page = stagehand.page;

// After (v3)
const page = stagehand.context.pages()[0];

Agent configuration (v2 → v3):

// Before (v2)
const agent = stagehand.agent({
  provider: "google",
  model: "gemini-2.5-computer-use-preview-10-2025",
  instructions: `You are a helpful assistant...`,
  options: {
    apiKey: GOOGLE_API_KEY,
  }
});

// After (v3)
const agent = stagehand.agent({
  cua: true,
  model: {
    modelName: "google/gemini-2.5-computer-use-preview-10-2025",
    apiKey: GOOGLE_API_KEY,
  },
  systemPrompt: `You are a helpful assistant...`,
});

Kernel SDK initialization (simplified):

// Before
const kernel = new Kernel({
  apiKey: process.env.KERNEL_API_KEY
});

// After
const kernel = new Kernel();

Reference

• Stagehand v3 Agent Docs
• Stagehand v3 Migration Guide