[FEATURE] Desktop: collapsed sidebar project groups should still show active sessions, not just the current one

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

In the desktop app, sidebar sessions are now grouped into collapsible per-project sections. I understand what this solves — before it, sessions from different projects were interleaved in one flat list, and picking up work in project B mid-session in project A pushed A's session down the list. Grouping fixes that.

But the collapsed state throws away the one thing I navigate by. A collapsed group shows either nothing, or just the current chat. So when I'm working in two projects concurrently and their groups are separated by several other projects in the list, every switch is: collapse the top group, scroll, expand the bottom group, find the session, work in it — and now the top project's session is no longer the most recent, so going back means collapsing again, expanding again, and hunting for it again. That cycle repeats all day.

Two things make it worse than it sounds:

Sessions in a group are frequently indistinguishable. Titles are auto-generated from the first prompt. I drive my work through a plugin's slash commands, so most of my sessions are titled some variation of <plugin>: plan or <plugin>: next — ten of them, identical, stacked. In the old flat list I could rename sessions to project — task and scan. Now the disambiguating layer is the group header, and the sessions inside it are a wall of the same string.

This is an accessibility regression for me specifically. I score in roughly the bottom 10–25th percentile for symbol search — finding a specific item in a dense field of similar-looking ones is genuinely slow for me. A flat list of distinct, self-authored labels was scannable. Nested identical labels under headers in a non-obvious order is materially harder, and the extra clicking compounds it. The feature reads as half-landed: it removed a burial problem and introduced a hunting one.

Proposed Solution

Make the collapsed state show every session with the activity indicator, not only the current one. If a collapsed group still surfaced any session that is running or carries the green dot, I would almost never need to expand a group at all — the sessions I'm actually working in would stay visible across every project simultaneously, which is exactly the set I'm switching between. The grouping keeps doing its job for the long tail of finished sessions.

This seems like the smallest possible change that fixes it: it's a change to what "collapsed" means, not to the grouping model.

Alternative Solutions

• Order project groups by most recent activity, so the projects I'm actively working in sit adjacent rather than separated by inactive ones.
• Let a project group be pinned open, so multiple groups can stay expanded.
• Make session renaming persistent and discoverable, so the in-group titles can be disambiguated by hand the way flat-list titles could be.
• Offer a flat "all recent sessions" view as an alternative sidebar mode.

The first proposal is the one I'd actually want; these are fallbacks.

Priority

Medium - Would significantly improve workflow

Feature Category

User interface

Use Case Example

I run two long-lived projects and move between them many times a session. With ~12 project groups in the sidebar and the two active ones far apart, switching costs a collapse, a scroll, an expand, and a visual hunt through identically-titled sessions. With active sessions visible in the collapsed state, it would cost one click.

Additional Context

Related: #81063 asks for a per-project display-name override. Different problem (naming/privacy rather than navigation), but the same sidebar surface.