Pin OpenAI CUA template browser viewport to 1920x1080

The OpenAI template created the browser with no explicit viewport,
leaving it on Kernel's default. Pin it to 1920x1080 to match the size
the template targets (and cua-agent's coordinate fallback), keeping it
consistent with the Anthropic (1280x800) and Gemini (1200x800) templates.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: dprevoznik

pkg/templates/typescript/openai-computer-use/index.ts

@@ -26,7 +26,10 @@ app.action<CuaInput, CuaOutput>(
     const start = Date.now();
     if (!payload?.task) throw new Error('task is required');
 
-    const browser = await kernel.browsers.create({ invocation_id: ctx.invocation_id });
+    const browser = await kernel.browsers.create({
+      invocation_id: ctx.invocation_id,
+      viewport: { width: 1920, height: 1080 },
+    });
     console.log('Kernel browser live view url:', browser.browser_live_view_url);
 
     const replay = await maybeStartReplay(kernel, browser.session_id, {