Repo hygiene & v2 docs

[bradgessler]

Clean-sheet cleanup.

• Relicense AGPL → proprietary (DONE on v2 branch).
• Purge .DS_Store litter and dead/empty files (e.g. near-empty meta-gem shims).
• Rewrite README/docs for the v2 architecture (Go client + Ruby server + protocol).
• Decide final gem/repo structure once client moves to Go.