feat(plugin): support removing multiple plugins at once

[git-hulk]

Summary

• add support for uninstalling multiple plugins in one command invocation
• update clime plugin uninstall args from single plugin to one-or-more plugin names
• process removals sequentially with per-plugin spinner output and an aggregate summary
• deduplicate repeated plugin names in args to avoid duplicate work
• aggregate failures and return a combined error while preserving successful removals
• add tests for arg validation and name deduplication helpers

Testing

• go test ./...

Closes #8