ultraplan: fails with 'Background tasks require a GitHub remote' even when remote is configured

Bug Description

/ultraplan fails with the error below even when a valid GitHub remote is already configured.

Error Message

ultraplan: cannot launch remote session —
Background tasks require a GitHub remote. Add one with `git remote add origin REPO_URL`.

Remote Configuration

A valid HTTPS remote (origin) was configured and tracking a remote branch that was fully up to date with commits pushed.

Steps to Reproduce

1. Initialize a git repo and create a private GitHub repo via gh repo create --private
2. Push an initial commit
3. Run /ultraplan from within the repo directory
4. Error appears despite remote being correctly configured

Environment

• OS: Linux WSL2 (6.6.87.2-microsoft-standard-WSL2)
• Shell: bash
• gh auth status: logged in to github.com