Plugin marketplace updater creates stray directory in CWD on WSL2 due to Windows-style path in git clone

Summary

When Claude Code updates the plugin marketplace on WSL2, it runs git clone with a Windows-style backslash path as the destination. Since WSL2 uses Linux path semantics (where \ is not a path separator), git interprets the Windows path as a literal directory name and creates it relative to the current working directory instead of at the intended absolute location.

Environment

• OS: WSL2 (Linux 6.6.87.2-microsoft-standard-WSL2)
• Platform: Windows + WSL2

What happened

A directory named literally C:\Users\jwa\.claude\plugins\marketplaces\claude-plugins-official was created inside my project directory (~/task-system/) — wherever Claude Code happened to be running at the time.

The directory was a full git clone of git@github.com:anthropics/claude-plugins-official.git, identical to the correctly-placed clone at ~/.claude/plugins/marketplaces/claude-plugins-official/.

Root cause

The plugin marketplace updater constructs the destination path using Windows path semantics (C:\Users\...\claude-plugins-official), then passes it to git clone executed in a WSL bash shell. In Linux, \ is a valid filename character, so git treats the entire Windows path string as a relative directory name and creates it under the current working directory.

Steps to reproduce

1. Run Claude Code in WSL2 with plugins enabled (e.g., superpowers@claude-plugins-official)
2. Trigger a marketplace update (e.g., on session start)
3. Observe a directory named C:\Users\<username>\.claude\plugins\marketplaces\claude-plugins-official created in whatever directory Claude Code was launched from

Expected behavior

The marketplace repo should be cloned to ~/.claude/plugins/marketplaces/claude-plugins-official (using the Linux path), not to a Windows-style path interpreted as a relative directory name.

Suggested fix

When running on WSL2, path construction for plugin/marketplace directories should use Linux-style paths (e.g., via wslpath conversion or by detecting the WSL environment and using $HOME instead of C:\Users\...).