The Worker previously owned the ShardDownloader directly via dependency
injection, which prevented --no-worker nodes from downloading and made
it impossible for multiple Workers to share a single downloader instance.
Moved download functionality to a new DownloadCoordinator component at
the Node level that communicates via the DOWNLOAD_COMMANDS pub/sub topic.
Workers now send StartDownload commands instead of calling the downloader
directly, and receive progress updates through the event-sourced state.
This decouples downloads from the Worker lifecycle and enables future
features like UI-triggered downloads to specific nodes and multi-worker
download sharing.
Test plan:
- Mostly tested in the next PR that adds explicit downloads/deletions to
the dashboard.
- Started a model that isn't downloaded - it works.
Jake Hillion
9357503c6f