[BUG] auto-update causes loss of plugin user settings, and update failure leads to plugin load failure

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?

When using claude-code, the current plugin is updated via auto-update to the path ~/.claude/plugin/cache/<marketplace>/<version>/<plugin>. If the plugin internally depends on stdio/http mcp and stores user privacy information or other user-specific settings inside the plugin folder, these settings are not preserved/copied into the new version folder during the auto-update. As a result, user settings are lost. Additionally, if auto-update fails, the plugin cannot be loaded at all.

What Should Happen?

After an auto-update, all previous user settings inside the plugin (especially privacy-related settings) should be automatically migrated or preserved into the new plugin folder. Even if an update fails, the plugin should remain loadable and usable.

Steps to Reproduce

1. Install and configure a plugin that depends on stdio/http mcp and contains user-specific settings (such as privacy info).
2. Allow the plugin to update via auto-update.
3. After update, check whether old settings are preserved under ~/.claude/plugin/cache/<marketplace>/<version>/<plugin>.
4. Test whether the plugin remains loadable if the auto-update fails.

Claude Model

_No response_

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.76

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

This issue causes users to suddenly lose privacy or critical configuration, severely impacting user experience. If auto-update fails, the plugin becomes completely unavailable, affecting all plugin functionality. Ideally, auto-update should automatically migrate user settings, and there should be a fallback or rollback mechanism to avoid total failure.