Add gap-1.5 to the roster tab triggers so icons and labels are not
glued together, and let the org chart tab scroll horizontally instead
of overflowing the page.
- Fetch current user's leadOrActual preference in roster page via payload.auth()
- Add RosterDisplayContext to avoid prop drilling through org chart components
- MemberCard shows 'Lead' or 'Actual' based on user preference
- Add preference radio buttons to PreferencesForm under Display section
- Update updatePreferences server action to save leadOrActual
- Add TODO for restyling radio buttons later
- Resolve parents via subAssignments instead of inferred member overlap
- Drop cyclic or dangling subassignment edges
- Render members only at their deepest unit; widen unit boxes and pluralize member counts
