Add a Connections sidebar section to group chats by host

What variant of Codex are you using?

macOS App

What feature would you like to see?

Feature request

When multiple computers are connected to the Codex desktop app, chats from
different hosts are mixed together in the sidebar.

Please add a collapsible Connections section below Projects. It should
list each connected device by its display name. Expanding or selecting a device
should show only the chats associated with that host.

Proposed structure:

• Connections
  • Device 1
    • Chat A
    • Chat B
  • Device 2
    • Chat C
  • Device 3
    • Chat D
• Projects
• Recents

Desired behavior

• Show every connected host by device name.
• Show online/offline or unavailable state.
• Expand a host to display chats from that host.
• Preserve each chat's existing project association.
• Allow selecting a host to filter the visible chat list.
• Persist expanded state and the selected host across app restarts.
• Clearly distinguish local, SSH, cloud, and remote-desktop hosts where applicable.

Motivation

When several connected computers contain similarly named projects or chats,
the current mixed list makes it difficult to tell where a task is running.
This increases the risk of opening, interrupting, approving, or handing off
the wrong task.

The desktop app already tracks the host associated with remote chats, so this
appears to be primarily a sidebar organization and filtering improvement.

Additional information

No response

Start with the macOS desktop app sidebar and the existing host association for remote chats. Trace how chat and project lists, host status, and app state are represented and persisted. Done means hosts are grouped in a collapsible Connections section with filtering, status display, project associations, and restored selection and expansion state.