Plugin-related CLI subcommands

See CLI/subcommands.md for the complete claude plugin command reference:

claude plugin install <plugin> [--scope user|project|local] — Install a plugin
claude plugin uninstall <plugin> [--scope user|project|local] [--keep-data] — Uninstall a plugin
claude plugin enable <plugin> [--scope user|project|local] — Enable a disabled plugin
claude plugin disable <plugin> [--scope user|project|local] — Disable a plugin
claude plugin update <plugin> [--scope user|project|local] — Update a plugin to the latest version
claude plugin list [--json] [--available] — List installed plugins
claude plugin validate <path> — Validate a plugin manifest and components
claude plugin search <query> — Search available plugins
claude plugin info <plugin> — Show detailed info about a plugin