Added

• New optional Spaces sidebar layout (General preferences → Sidebar → Layout). Toggle between the flat Normal sidebar and a Spaces layout where projects are grouped into user-defined spaces and one space is visible at a time. Existing projects land in an auto-created Default space on first activation, so nothing disappears.
• A dedicated Spaces tab in Preferences for managing spaces: name, SF Symbol icon (5 starter symbols with a Show more to reveal the full 70), and which projects belong where. A project lives in exactly one space; moving it elsewhere is one click.
• A proxy-icon bar at the bottom of the sidebar shows every space; the active one is highlighted, hover reveals its name, click jumps to it with a spring-physics animation. Swipe with two fingers on the trackpad to drag-and-snap between spaces; wrap is circular so swiping past the last space lands on the first.
• ⌃1–⌃9 activates Space N. The existing ⌘1–⌘9 pane shortcuts now scope to panes in the active space when Spaces is on, so the shortcuts always line up with what's visible.