- Backend: subscribe/unsubscribe API now accepts optional user_id to manage other users
- Frontend: replace manual avatar stacking with shadcn AvatarGroup component
- Frontend: replace disabled-checkbox Popover with Command+Popover combo (Linear-style)
- Search/filter workspace members
- Click to toggle subscription (checkbox)
- Shows reason badge (Assignee, Creator, etc.) for auto-subscribed users
- Clean up duplicate status_change type (keep only status_changed)
- All tests pass (Go + TypeScript)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>