Plugin installer resolves wrong home directory on macOS

Bug Description

The plugin installer fails to install marketplace plugins on macOS because it resolves the home directory as /home/claude/ instead of the actual user home directory (e.g., /Users/<username>/).

Steps to Reproduce

1. Open Claude Code on macOS
2. Run /plugin
3. Navigate to a marketplace plugin (e.g., frontend-design from claude-plugins-official)
4. Select any install scope (user, project, or local)

Expected Behavior

Plugin installs successfully, resolving the source path relative to the actual marketplace directory on disk:

/Users/<username>/.claude/plugins/marketplaces/claude-plugins-official/plugins/frontend-design/

Actual Behavior

Installation fails with:

Error: Failed to install: Source path does not exist:
/home/claude/.claude/plugins/marketplaces/claude-plugins-official/plugins/frontend-design

Analysis

The marketplace repo is correctly cloned to ~/.claude/plugins/marketplaces/claude-plugins-official/ and the plugin directory exists on disk. The marketplace.json uses relative source paths (e.g., "source": "./plugins/frontend-design"), but the installer resolves these relative to /home/claude/.claude/plugins/... instead of the actual $HOME on macOS (/Users/<username>/).

This appears to affect all marketplace plugins with relative source paths, not just frontend-design.

Environment

• OS: macOS (Darwin 25.2.0)
• Claude Code version: Latest (as of 2025-02-10)
• Shell: zsh