[Bug] Extension fails to activate on Windows - hardcoded Linux path in versions 2.1.51+

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Description:
Extension fails to activate on Windows starting from version 2.1.51.
Last working version is 2.1.49.

Error:
TypeError: The argument 'filename' must be a file URL object, file URL string,
or absolute path string. Received 'file:///home/runner/work/claude-cli-internal/
claude-cli-internal/build-agent-sdk/sdk.mjs'

Versions affected: 2.1.51, 2.1.55
Last working version: 2.1.49
OS: Windows
VS Code version: (add yours here)

Steps to reproduce:

1. Install Claude Code extension version 2.1.51 or higher on Windows
2. Reload VS Code
3. Extension fails to activate with above error

Expected: Extension activates normally
Actual: Extension fails with hardcoded Linux path error

I cannot check "using latest version" because the latest version (2.1.55) is the broken one. Last working version is 2.1.49. I have tested 2.1.51 and 2.1.55 and both are broken on Windows.

What Should Happen?

The extension should activate successfully on Windows without any errors.
Claude Code sidebar and editor commands (such as claude-vscode.sidebar.open
and claude-vscode.editor.openLast) should be available and functional after
VS Code loads, just like they were in version 2.1.49.

Error Messages/Logs

Steps to Reproduce

1. Install Claude Code extension version 2.1.51 or higher on Windows
2. Reload VS Code
3. Observe that the extension status shows "Not yet activated"
4. Try to open Claude sidebar or run any Claude command
5. Get error popup: "command 'claude-vscode.sidebar.open' not found"
6. Check Extension Host logs and see the TypeError with hardcoded Linux path

Note: Downgrading to version 2.1.49 fixes the issue completely.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.49

Claude Code Version

2.1.55

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_