fix(clean): keep enabled Claude Code plugin state dirs off the orphan list (#889)

The orphan-dotdir hint checked a static safe list, PATH binaries, GUI
apps and LaunchAgents, but knew nothing about Claude Code plugins. A
plugin owns a state directory such as ~/.cc-safety-net without
installing a matching binary, so active plugin state was reported as a
"Potential orphan dotfile".

Collect enabled plugin name tokens from ~/.claude/settings.json
(enabledPlugins) and ~/.claude/plugins/installed_plugins.json, and skip
any dotdir whose name embeds an enabled plugin token.