bb-plugin-authoring

# Author BB plugins A BB plugin is a TypeScript package that can add server behavior, agent capabilities, host-rendered UI, or a frontend bundle. Use the current SDK types and repository source as the contract. This skill routes to detailed references, but the installed BB version decides the exact API. ## Implement and verify Inspect the affected package and current SDK declarations to select backend, frontend, or both. Build the plugin and verify the affected contracts and user workflow. Install or reload when a live check is needed for the requested work. Use bb plugin new <name> for a new plugin. The scaffold includes frontend files. Remove `bb.app` and those files when the plugin is headless. Every new public Plugin SDK surface starts with an experimental\_ prefix and an entry in docs/api_to_audit.md. Add its Plugin Guide card and API inventory in the same change. ## Read only the relevant reference ### Start, package, and release - Read references/quickstart.md for package structure, manifest fields, scaffold output, build, install, and the first plugin. - Read references/distribution.md for exact API lookup, Git or npm release, multi-plugin repositories, and custom marketplaces. ### Backend - Read references/backend-foundation.md for the factory, logging, settings, storage, server information, and host access. - Read references/backend-sdk.md for projects, environments, threads, interactions, provider models, browser sessions, and event history. - Re...