[BUG] Desktop app sidebar groups two separate project sessions under one entry

Preflight Checklist

• [x] I have searched existing issues 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?

Sidebar grouping bug in the Claude desktop app: sessions from two separate projects are being displayed under a single project group, even though on disk they're stored in separate ~/.claude/projects/ folders with distinct cwd values.

Possible clue from Claude app: one project folder uses an underscore in its name, which gets encoded to a hyphen in the projects folder path. The grouping logic may be colliding on that rewrite.

Restarting the app and using the sidebar filter/group controls did not fix it. Data on disk is correct — this is purely a display issue.

What Should Happen?

Each project directory on disk should appear as its own separate group in the sidebar, with only its own sessions nested underneath. Two projects with different cwd values (and different folders under ~/.claude/projects/) should never be merged into a single sidebar entry, regardless of how their names are encoded.

Error Messages/Logs

Steps to Reproduce

This is a display issue on my Claude app.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.76 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_