WorkspaceChatSidebar

One panel: a persistent header (search + "New Workspace") over collapsible, drag-reorderable workspace sections (each listing its channels), a divider, then Chats — filterable, windowed to the most recent 4 with a "show more" expander. Drag a section header to reorder workspaces relative to Chats; drag a channel row to reorder within its workspace; drag a pinned chat row to reorder the pinned set. Selection: {"type":"channel","id":"s-planning"}