fix: replace fs.promises.mkdtemp with mkdir for Workers compatibility

[ebrainte]

Summary

• Replace fs.promises.mkdtemp with fs.promises.mkdir + random suffix in 3 call sites
• Fixes runtime crash when using @cloudflare/playwright in a Cloudflare Worker

Problem

Cloudflare Workers' nodejs_compat (via unenv) does not implement fs.mkdtemp or fs.promises.mkdtemp. When deploying the Playwright MCP example (or any Worker using @cloudflare/playwright), the Worker crashes at runtime with an error like:

TypeError: fs.promises.mkdtemp is not a function

This affects @cloudflare/playwright@1.1.2 (and likely earlier versions).

Fix

Replace mkdtemp(prefix) with mkdir(prefix + randomSuffix, { recursive: true }) in:

File	Line	Description
packages/playwright-core/src/server/browserType.ts	158	Artifacts directory creation
packages/playwright-core/src/server/browserType.ts	167	User data directory creation
packages/playwright-core/src/server/chromium/chromium.ts	92	CDP artifacts directory creation

The random suffix uses Math.random().toString(36).slice(2), providing sufficient uniqueness for temporary directory names while using only fs.promises.mkdir which IS available in Workers.

Requires

compatibility_date >= 2025-09-23 in the Worker's wrangler.toml for fs.promises.mkdir to be available.

Testing

Verified by deploying the cloudflare/playwright-mcp example Worker with these changes patched via patch-package. The Worker successfully launches browsers, navigates pages, and takes screenshots without any mkdtemp-related errors.