Add GitHub auth command #6
Description
Summary
Implement the Phase 4 authentication flow so users can run a dedicated sess auth login command that securely stores credentials and integrates with subsequent commands.
Motivation
- README.md Phase 4 roadmap and docs/technical-spec.md call for a first-class auth command.
- Relying solely on gh CLI limits users who expect in-tool authentication.
Scope
- Add a new sess auth login (or sess auth) command wired through the Cobra layer.
- Implement OAuth or PAT-based login with secure storage (OS keychain or encrypted config as documented).
- Detect and reuse existing gh authentication when available.
- Provide clear status and error handling aligned with docs/cli_design_guide.md.
- Update session workflows to respect the new auth path.
Out of Scope
- Non-GitHub identity providers (covered in future phases).
- UI for token revocation.
Acceptance Criteria
- Users can authenticate via the new command without leaving the CLI.
- Subsequent commands succeed without requiring manual gh auth login.
- Stored tokens meet the security guidance in docs/technical-spec.md.
References
- README.md (Phase 4 roadmap)
- docs/technical-spec.md
- docs/DEVELOPMENT.md (auth notes)