[Feature] Drag-to-reorder GROUPS in the left sidebar (same as sessions)

Summary

In the desktop app's left sidebar (FleetView), individual sessions can already be dragged and reordered. Please allow the same drag-and-drop reordering for whole GROUPS (project/group headers), so the order of the groups themselves can be arranged manually.

Current behavior

• Sessions within the list can be grabbed and moved.
• The groups (the collapsible project/folder headers) cannot be grabbed or reordered — their order is fixed (recent activity / creation order).

Requested behavior

• Grab a group header and drag it up/down to reorder groups, exactly the way sessions can already be dragged.
• The chosen group order should persist across restarts.

Why

Users who manage many projects want a stable, intentional ordering of their groups (e.g. a primary "command center" group pinned at the top), independent of recent activity. Manual drag-reorder is the most direct way to achieve this.

Related

• #66196 — "[Feature] Sidebar: control project/group sort order (alphabetical / pin to top)" lists "Drag-to-reorder groups" as a proposed solution but was closed as COMPLETED; drag-reordering of groups still does not appear to work in the current desktop app, so this issue tracks that specific capability.

Environment

• Claude Code desktop app (FleetView)
• macOS (Darwin 25.4.0)