POST /v1/user/me/avatar and /v1/calendars/:id/cover; GET /v1/media; UPLOAD_DIR on eventhub-data volume; MIME/size limits. Refs EventHub/EventHubBack#71 Refs EventHub/EventHubSpec#8
Publish erlang-builder and erlang-runtime as :latest, use them in prod and API test builds, auto-collect NIF libs, and sync CI to pull/push bases before eventhub build. Co-authored-by: Cursor <cursoragent@cursor.com>