CLAUDE_CONFIG_DIR not respected for plugins/marketplaces directory

Description

When using CLAUDE_CONFIG_DIR to specify a custom configuration directory, Claude Code still creates and uses ~/.claude/plugins/marketplaces/ instead of respecting the custom path.

Steps to Reproduce

1. Set CLAUDE_CONFIG_DIR to a custom path (e.g., ~/.claude-af)
2. Launch Claude Code
3. Observe that ~/.claude/plugins/marketplaces/ is created

Expected Behavior

All Claude Code files should be stored in the directory specified by CLAUDE_CONFIG_DIR. The plugins/marketplaces directory should be created at $CLAUDE_CONFIG_DIR/plugins/marketplaces/.

Actual Behavior

• Main configuration, history, and settings correctly go to $CLAUDE_CONFIG_DIR
• Plugins/marketplaces directory is hardcoded to ~/.claude/plugins/marketplaces/

Environment

• macOS (Darwin 25.1.0)
• Claude Code version: 2.0.x
• Using direnv to set CLAUDE_CONFIG_DIR per-directory

Use Case

Separating Claude Code configuration between multiple accounts (work vs personal) by using different CLAUDE_CONFIG_DIR values. The hardcoded ~/.claude path breaks full isolation.

Workaround

Currently using a symlink (ln -s ~/.claude-af ~/.claude) as a workaround, but this defeats the purpose of account separation.