feat: native /goal for Codex and Claude, with goal status in the UI (#15592)

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
a172e1c4e8Theo Browne committed on 10/5/2026, 9:12:29 PM· committed by GitHubparentf32c23c
26 files changedLine totals unavailable