chore(release): publish `@castui/cli` v0.1.0 (hello message)

[thopatevijay]

• Finalize package.json fields (name, version, description, repository).

• Add publishConfig: { "access":"public" }.

• Run npm publish --access public (or npm publish --registry <if org>).

• Update repo README with release notes.

Acceptance criteria

• npm info @castui/cli returns published version 0.1.0.

• npx @castui/cli prints Welcome to CastUI for a new user (no local linking required).

• Release tag created in GitHub v0.1.0.