Add "retrospective" to validPhases so non-TDD skills pass Validate().
Return []Entry{} instead of nil in session.Read when no file exists,
so JSON serialisation produces [] rather than null.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Remove cmd/supervisor/supervisor binary from git (was accidentally
committed) and add it to .gitignore. Move LITELLM_API_KEY from the
prompt string into the subprocess env, preventing it from appearing
in error log output when JSON parsing fails.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
