Loading thread item

A placeholder for a thread list item being fetched from network

Skeleton for a row in a thread/message list. Renders as a 2-column 2-row grid: a loading avatar on the left spanning both rows, a half-width loading line on the top right (sender/title), and a full-width loading line on the bottom right (preview/snippet). Use it while the underlying thread data is loading to hold layout and indicate the shape of incoming content.