Plugin commands give more specific errors and resolve names across marketplaces

The plugin install and uninstall commands have changed in a few ways:

• Failures are sorted using specific codes such as plugin_folder_held, marketplace_policy_blocked and not_installed.
• An unknown error that has a failure code now reports that code instead of a generic error.
• If an install changed nothing, --config values are not applied, and you are warned that they were not saved because the command changed nothing.
• If a plugin name matches the same plugin from another marketplace, Claude Code uses that installed plugin under its existing name and tells you so.

Usage reports for failed plugin commands now also include the failure code and the matched name.