bug: `claude plugin uninstall` gives contradictory scope error messages

Bug Description

The claude plugin uninstall command gives contradictory error messages about plugin scope, making it impossible to uninstall a plugin via CLI.

Steps to Reproduce

1. Have a plugin installed (in this case pr-review-toolkit@claude-code-plugins was in ~/.claude/settings.json under enabledPlugins)
2. Try to uninstall without specifying scope:

``bash
claude plugin uninstall pr-review-toolkit
`
**Error**: Plugin "pr-review-toolkit" is installed in project scope, not user. Use --scope project to uninstall.`

1. Try with --scope project:

``bash
claude plugin uninstall pr-review-toolkit --scope project
`
**Error**: Plugin "pr-review-toolkit" is not installed in project scope. Use --scope to specify the correct scope.`

1. Try with --scope user:

``bash
claude plugin uninstall pr-review-toolkit --scope user
`
**Error**: Plugin "pr-review-toolkit" is installed in project scope, not user. Use --scope project to uninstall.`

1. Try with full plugin name including marketplace:

``bash
claude plugin uninstall "pr-review-toolkit@claude-code-plugins" --scope user
`
**Error**: Plugin "pr-review-toolkit@claude-code-plugins" is installed in project scope, not user. Use --scope project to uninstall.`

Expected Behavior

The CLI should correctly identify which scope the plugin is installed in and allow uninstallation with the appropriate --scope flag.

Actual Behavior

The CLI gives contradictory error messages - it says the plugin is in project scope, but when you specify project scope it says it's not there, creating an impossible loop.

Workaround

Manually edit ~/.claude/settings.json and remove the plugin from the enabledPlugins object.

Environment

• Claude Code version: (current as of 2025-01-04)
• OS: macOS Darwin 24.6.0
• Plugin location: ~/.claude/settings.json under enabledPlugins

Additional Context

The plugin was configured in user settings as:

"enabledPlugins": {
  "pr-review-toolkit@claude-code-plugins": true,
  ...
}

The scope detection logic appears to be incorrectly identifying the plugin's location.