Moves plex's API client and tools out of the shared hal sdk into the module,
so a Plex API change rebuilds only plex. Tools: status, search, sessions,
recently-added, refresh. And a real event design: it emits playback
started/stopped and item.added by watching the server, and consumes
module.*.download.completed to rescan so a downloader's fetch becomes a
visible item. Typechecks against the sdk; manifest parses with its emits/
consumes and broker own-secret.
Claude-Session: https://claude.ai/code/session_01LrgweAeERJYBg88c5cKDzF
jschoubben