Copilot Desktop: Show child sessions and their status in an expandable Projects navigation tree #5527

Title

Show child sessions and their status in an expandable Projects navigation tree in Github Copilot Desktop.

Description

A project has its own session, which can create child sessions. Please reflect that hierarchy in the Projects section of the left navigation by letting users expand a project to see its child sessions.

Each child session should show its current status, such as running, waiting for input, blocked, or completed. Selecting a child session should open it directly, while selecting the project should continue to open the parent session.

This would make it easier to see which child sessions are running and which need attention without opening the parent session to find them.

Expected behavior:

• Expand or collapse a project to show or hide its child sessions.
• Show a clear status indicator next to each child session, especially when it needs user input or approval.
• Open a child session directly from the tree.
• Keep the parent project session accessible for coordinating the overall work.