docs: clarify create-starter distribution surface

[heznpc]

Summary

• remove the remaining implication that create-starter should eventually use a public multilingual landing page
• state the actual distribution surface: CLI/MCP/plugin/Desktop extension tooling
• keep root README English-only and localized Korean docs under docs/ko/README.md

Verification

• npm test (150 pass)
• npm audit --audit-level=moderate
• git diff --check
• grep check for create-starter Pages URL/docs/index/data-i18n/data-lang/public landing wording