Federation and Bundler Decision — Bun + Rsbuild + Module Federation, Workspace State, Optional Chat

We federate: Module Federation on rsbuild, bun over turbo, and state of truth in `@augment-it/workspace` — chat is just one consumer.

• Exploration
• Augment-It
• Module-Federation
• Rsbuild
• Bun
• In-App-Agent-Chat
• Workspace-Pattern
• Architecture-Decision