Update File I/O Docs

[tembo]

Summary

Update Playwright file I/O documentation with:

• New download behavior using behavior: 'default'
• Simplified file upload examples using setInputFiles()
• Removed manual file upload to browser VM
• Updated download directory to use ~/Downloads

Description

This PR updates the file I/O documentation to:

• Recommend behavior: 'default' for browser downloads
• Simplify file upload examples using Playwright's native setInputFiles() method
• Remove complex file transfer steps
• Use standard ~/Downloads directory for downloads

Changes include:

• Updated code examples in TypeScript and Python
• Added note about default download behavior
• Demonstrated file upload with local file and buffer

Implementation Checklist

• Updated file I/O documentation
• Verify examples work with current Playwright version

Testing

• Verified examples run correctly
• Confirmed mintlify dev works

Related Issue

Fixes KERNEL-793

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Note

Updates File I/O docs to streamline Playwright workflows and reduce manual file handling.

• Downloads: switch to Browser.setDownloadBehavior with behavior: 'default', capture filePath from downloadProgress, and update wait helpers to accept a full filePath (deriving dir/name internally)
• Example code (TS/Python): remove hardcoded download dir, adjust event listeners, error handling, and local save paths; add note about default behavior and polling with listFiles
• Uploads: replace remote FS write steps with direct setInputFiles() using fetched buffer (TS uses fetch, Python uses httpx); simplify selectors and logging
• Minor doc copy edits and link to related APIs; .gitignore now ignores .env

^{Written by Cursor Bugbot for commit a8b4bd9. This will update automatically on new commits. Configure here.}

[dprevoznik]

Summary

Updates the File I/O documentation with fixes and improvements to both download and upload examples.

Downloads

Fixed a critical path bug in the Playwright download examples (TypeScript & Python):

• The examples were using os.homedir()/Downloads which returns the local machine's home directory, not the remote Kernel browser's path
• Now correctly captures filePath from the CDP downloadProgress event, which provides the actual path where the file was saved on the remote browser (/home/kernel/Downloads/...)
• Updated waitForFile() helper to accept a full file path
• Updated the documentation Note to explain the filePath field in CDP events

Uploads

Simplified upload examples (TypeScript & Python):

• Replaced two-option pattern (local file path vs buffer from local file) with a single streamlined approach
• New pattern fetches an image from a URL and uploads it via buffer - more practical for real-world use cases
• Example uses https://www.kernel.sh/brand_assets/Kernel-Logo_Accent.png
• TypeScript uses native fetch(), Python uses httpx (already a dependency of the kernel SDK)

Testing

All four examples (TypeScript/Python × Download/Upload) were tested and verified working against live Kernel browser sessions.