What problem does it solve? Developers wiring the REASON editor's sidebar into a host application need to understand its controlled-component API, five stackable panels, inferred split view, and localStorage-backed file-source system without reading the entire package source. ## Core Features & Use Cases - Sidebar Integration: Inject Sidebar and SidebarContent into ReasonDocs via props, keeping the one-way dependency between react-reason-editor and react-reason-editor-sidebar intact. - Panel & Split View Management: Control five panels (Open Tabs, Files, Outline, Related, AI) with togglePanel and sortPanels, where selecting two panels on a side creates a resizable split view. - File Sources & Storage Backends: Configure seven storage backends (local, SSH, S3, R2, B2, Google Docs, Turso) through localStorage-backed CRUD helpers rendered in the SidebarFooter picker. - Use Case: A developer building a document workspace mounts ReasonDocs, passes the sidebar components, implements onMove and onSetExpandedFolders callbacks so drag-and-drop and folder expansion persist, and enables the S3 file source for remote documents. ## Quick Start Ask the assistant to wire the Sidebar and SidebarContent components from react-reason-editor-sidebar into a ReasonDocs host with controlled document state and a working file-source picker.