feat: rename CLI package to @ruma-ui/cli, update command references

[RanitManik]

Summary by CodeRabbit

• New Features

  • The CLI is now available as the scoped @ruma-ui/cli package.
  • CLI releases support both prerelease and stable publishing.

• Bug Fixes

  • Updated CLI guidance and validation messages to use the correct scoped package commands.

• Documentation

  • Updated installation, homepage, component, and CLI documentation examples to use npx @ruma-ui/cli``.