Directory marketplace plugins not auto-enabled in settings.json

Bug Description

When installing a plugin from a directory-based marketplace, Claude Code adds the plugin to installed_plugins.json but does NOT add it to settings.json enabledPlugins. This requires manual intervention to enable the plugin.

Steps to Reproduce

1. Create a directory-based marketplace in known_marketplaces.json:

``json
"local-dev": {
"source": {"source": "directory", "path": "C:\path\to\marketplace"},
"installLocation": "C:\Users\Me\.claude\plugins\marketplaces\local-dev"
}
``

1. Install a plugin: claude plugin install rlm@local-dev
2. Check ~/.claude/installed_plugins.json - plugin is listed ✓
3. Check ~/.claude/settings.json enabledPlugins - plugin is NOT listed ✗
4. Plugin hooks don't work until manually added to settings.json

Expected Behavior

Plugin should be auto-enabled in settings.json just like GitHub marketplace plugins.

Actual Behavior

Plugin is installed but not enabled. Manual edit required:

"enabledPlugins": {
  "rlm@local-dev": true
}

Environment

• Claude Code Version: v2.1.6
• OS: Windows

Workaround

Manually add plugin to settings.json after installation.

Impact

Plugins appear "installed" but don't function, causing confusion. Hooks silently fail to load without clear error messages.