[BUG] VS Code extension v2.1.55 fails to activate on Windows — hardcoded Linux build path

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?

The Claude Code VS Code extension v2.1.55 fails to activate on Windows 11. The extension installs successfully but no commands are registered and no output channel appears.

What Should Happen?

Extension should activate normally and register all commands.

Error Messages/Logs

From VS Code extension host log (`exthost.log`):

  2026-02-24 22:44:38.336 [info] ExtensionService#_doActivateExtension Anthropic.claude-code, startup: false, activationEvent: 'onStartupFinished'
  2026-02-24 22:44:38.371 [error] Activating extension Anthropic.claude-code failed due to an error:
  2026-02-24 22:44:38.371 [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'
        at Object. (c:\Users\XXXX.vscode\extensions\anthropic.claude-code-2.1.55-win32-x64\extension.js:45:4848)

  The path `file:///home/runner/work/claude-cli-internal/claude-cli-internal/build-agent-sdk/sdk.mjs` is a Linux CI runner path that was hardcoded into the Windows build artifact.

Steps to Reproduce

1. Install Claude Code extension v2.1.55 on Windows
2. Open any project in VS Code
3. Extension fails to activate — no commands available, no output channel

## Expected Behavior

Extension should activate normally and register all commands.

## Environment

• OS: Windows 11 Pro (10.0.26200)
• VS Code: Latest
• Extension version: 2.1.55 (win32-x64)
• Claude CLI version: 2.1.55
• Extension path: anthropic.claude-code-2.1.55-win32-x64

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.55

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

• The CLI (claude in terminal) works fine — only the VS Code extension is broken
• Tried: full uninstall/reinstall, reload window, disabling other extensions — none fixed it
• This appears to be a build/packaging issue introduced in v2.1.55