[FEATURE] Desktop: group the Code-tab sidebar by machine, then by project

Context
I run Claude Code Desktop on 4 Windows PCs in my clinic (TDOOFFICE, TDOSTUDIO, TDOTOMO, TODOCART), all signed in to the same account with Remote Control enabled. Being able to reach sessions on other machines is great, but the sidebar now mixes everything in one list: ~200 local sessions plus ~90 Remote Control sessions from the other PCs.

Problem

1. Nothing in the sidebar shows which machine a session belongs to. Remote Control rows only say "Remote Control", with no hostname.
2. The same session often appears twice (the local row plus its Remote Control mirror, e.g. "F1.4", "Plano botões sobrepostos"), and I can't tell which copy runs where.
3. Several PCs use the same project paths (a synced Dropbox folder), so "group by project" merges sessions from different machines under one folder heading.
4. Workaround tried: one custom section per PC. It doesn't work. A custom section can only group by date/state/none ("project" is refused inside a section), so I lose the per-project grouping I rely on. Routine runs can't be moved either. I reverted it.

Request

• A "Group by: Machine" option, with a nested project grouping inside each machine (Machine → Project → Sessions).
• Show the hostname (or a user-editable machine label) on every session row and in the session header, local and Remote Control alike.
• Collapse a local session and its Remote Control mirror into one row, tagged with the machine it runs on.
• Optional: an online/offline indicator per machine.

Why it matters
I switch between PCs all day (office, video studio, CBCT room). Without a machine label I keep opening the wrong session or the wrong machine's copy, which is risky when a session controls hardware or production systems on that specific PC.

Environment
Claude Code Desktop (Code tab), Windows 11 Pro, 4 machines on one account, Remote Control enabled.