#7121 improvement(cli): clarify npm package readmes

Summary

• Rewrite the Sim CLI README around npm installation, login, profiles, useful commands, and automation
• Expand the sim-setup README with prerequisites, lifecycle commands, capability setup, and data-safety guidance

Type of Change

• Improvement

Testing

• bun run lint
• bun run apps/sim/scripts/check-block-registry.ts origin/staging
• bun run check:audits
• 66 Sim CLI profile and authentication tests
• 7 sim-setup argument parser tests

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)