Pulumi Cloud org model + state backup :: Business Bootstrap

Summary

Added Pulumi Cloud org model: CLI vs SaaS state, Individual = no invites, Team/OSS/self-hosted alternatives, ephemeral agent claim gotcha.
Added Back up Pulumi stack state: stack export/import, S3/GCS/file backends, Google Drive as offline copy (not a backend); preferred local CLI is rclone (multi-provider; remotes such as gdrive: / digitalocean-spaces:), not RepoDrive.
Cross-linked from Org infra index, org infra pattern, email checklist, and General Knowledge Technology → Infrastructure.