[FEATURE] Desktop: allow overriding the sidebar project group name (currently forced to GitHub repo name)

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, sessions are grouped in the sidebar by git root, and the group label is taken from the GitHub remote's repo name (the githubRepoPaths mapping in ~/.claude.json, with the org prefix dropped) rather than the local directory name.

My checkout lives at ~/repo/company/fw2, but its origin remote is git@github.com:company/webapp.git, so the sidebar group is labeled "webapp". I think of this project as "fw2" — the generic repo name "webapp" is unhelpful, and if I had two projects whose repos were both named webapp under different orgs, the labels would collide.

Proposed Solution

Either automatically prefer the more specific name, folder over the repo, or allow me to specify the name of the project.

Unwanted solution: switch entirely to custom groups.

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

Configuration and settings

Use Case Example

_No response_

Additional Context

_No response_