[BUG] Cowork desktop: session panel's "Working folders" file tree replaced by unlabeled "Context" chips — connected .md files no longer openable in-app (1.49585.0, Windows)

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

The right-hand session panel in Cowork no longer exposes connected folders as a browsable tree.

In sessions created since roughly 2026-09-09, the panel shows a "Context" section in which:
- connected folders appear as a horizontal row of chips, with only the last folder's name legible and the rest truncated to bare icons
- nothing expands
- there is no file tree
- no file can be opened or previewed
- the project instructions entry is gone

The folders are still mounted and the model can still read them, so this is a UI regression rather than a loss of access. The effect is that a project built on a library of local markdown reference files can no longer be read inside the app.

The panel format appears bound to when the session was created, not to the installed build. On this same 1.49585.0 build, older sessions in the same project still render the old "Working folders" tree while new sessions render the "Context" chips. That points to a per-session panel variant rather than a global redesign, so this may be a flag or migration issue rather than an intended change.

### What Should Happen?

The panel should show a "Working folders" section in which:
- each connected folder is listed by name and can be expanded
- files inside an expanded folder are listed and clickable
- clicking an .md file opens it for reading in the app
- the project's instructions file surfaces as its own clickable entry, shown as "Instructions · CLAUDE.md"

This is how sessions created on or before 2026-09-08 still render on this same build.

### Error Messages/Logs

```shell
None. The change is silent: no error, no warning, no failed load. The panel simply renders in a different format.
```

### Steps to Reproduce

1. Open a Cowork project on Windows desktop that has several local folders connected as context. Mine has five, all OneDrive-synced local paths holding markdown libraries.
2. Start a new session in that project.
3. Look at the session panel on the right: it shows a "Context" row of collapsed folder chips with no expansion and no file access.
4. Reopen a session in the same project that was created before 2026-09-09: it still shows the "Working folders" tree with expandable folders and clickable files.

### Claude Model

Opus

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

_No response_

### Claude Code Version

1.49585.0

### Platform

Anthropic API

### Operating System

Windows

### Terminal/Shell

Windows Terminal

### Additional Information

Environment
- App version: 1.49585.0
- Electron: 44.2.0
- Node: 24.20.0
- Platform: Windows, win32 x64
- Area: Cowork, desktop app, session context panel
- Connected folders in the affected project: 5

Timing
- Last known good: sessions started on or before 2026-09-08
- First observed bad: sessions started 2026-09-09 to 2026-09-10

Impact
This project is reference-heavy by design: five connected folders of markdown holding a methodology library, system rules, and a shared feedback queue. Reading those files in the panel was the normal way to check a rule or a framework mid-session. With the tree gone, the options are leaving the app for File Explorer or asking the model to print file contents into the conversation, which is slower and consumes context for something that used to be a click. No data loss. Severity is usability, but high-frequency usability for anyone running Cowork against local folder libraries.

Related
Same panel and same pattern as the Cowork context-panel regressions filed during the Chat/Cowork merge rollout, notably #76694, where the Cowork Context menu was replaced wholesale with the Chat-style knowledge menu and folder linking was lost for new projects. This is a distinct symptom: folder linking still works here, but the folders can no longer be browsed.

Question
Is the collapsed "Context" chip row the intended replacement for the "Working folders" tree, or is the tree expected to return? Nothing in the published changelog through 1.46388.1 describes removing it, and this build is newer than the latest published notes.

Reproduce this in the Cowork desktop session panel on Windows with several connected folders, then compare a session created on or before 2026-09-08 with one created after 2026-09-09. Use related issue #76694 for context. Done means the panel restores expandable Working folders, clickable files including .md files, and a visible Instructions · CLAUDE.md entry.

Rédigé par le modèle d'indexation à partir du texte de l'issue.