fix(computer): add PowerShell screenshot fallback for Windows Claude Code environments

[Copilot]

npx @midscene/computer connect fails during health check on Windows when invoked from Claude Code (or similar MCP hosts), while the same command works fine in a standalone terminal. The screenshot step crashes with a garbled error—the Chinese "command not recognized" message in GBK encoding read as UTF-8:

Error: Failed to take screenshot: Error: Command failed: cmd.exe /c ...\screenCapture_1.3.2.bat ...\screenshot.png
'screenCapture_1.3.2.exe' ♦♦♦♦♦ζ♦♦♦♦н♦♦♦♦Χ♦♦♦♦б♦♦♦♦еij♦♦♦

Root cause: screenshot-desktop compiles a .NET exe at runtime from a polyglot .bat/C# file and runs it from %TEMP%\screenCapture\. Claude Code's environment (UTF-8 code page 65001 and/or AppLocker/WDAC policies) prevents that dynamically-compiled, unsigned exe from being located or executed.

Changes — packages/computer/src/device.ts

• New screenshotViaWindowsPowerShell() method: takes a screenshot via powershell.exe using System.Windows.Forms.Screen + System.Drawing.Graphics.CopyFromScreen. The script is passed via -EncodedCommand (UTF-16LE base64), sidestepping shell-quoting and code-page issues entirely. PowerShell is a signed Microsoft binary not subject to the same execution restrictions.
• Fallback in screenshotBase64(): on Windows, if screenshot-desktop throws, the PowerShell path is tried automatically; both errors are surfaced if both fail.
• Security: displayId is sanitized ([a-zA-Z0-9\\.\-_:] only) before interpolation into the PowerShell string to prevent injection.
• Temp file uniqueness: process.pid + Date.now() + random suffix avoids collisions under concurrent calls.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• www.npmjs.com
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Bug]: Error occurs when triggering Midscene with skills in Claude Code</issue_title>
<issue_description>### Version

System:
    OS: Windows 11 10.0.26200
    CPU: (20) x64 Intel(R) Core(TM) i5-14600KF
    Memory: 15.88 GB / 31.84 GB
  Browsers:
    Edge: Chromium (141.0.3537.57)

Details

在单独的命令行可正常执行

但是在Claude Code中执行报错

Reproduce link

NA

Reproduce Steps

在Claude Code中执行npx @midscene/computer@1 connect或直接使用工具触发。
我试了我自己的电脑，还有阿里的云电脑都不行。</issue_description>

Comments on the Issue (you are @copilot in this section)

@quanru Please upload the completed log.

• Fixes [Bug]: Error occurs when triggering Midscene with skills in Claude Code #2150

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