Move SuperadminDashboard out of RoleDashboards.tsx #143

What this is for

RoleDashboards.tsx is a 3,100+ line file holding all 8 role dashboards. We're moving each one into its own file so the codebase is easier to navigate. This is the biggest and most complex dashboard — do this one last, after a couple of the smaller ones from #136 feel familiar.

What to move

export const SuperadminDashboard (~694 lines) — the dashboard shown to Superadmin-role users.

Steps

1. Create frontend/src/components/dashboards/SuperadminDashboard.tsx.
2. Cut the SuperadminDashboard component out of RoleDashboards.tsx into the new file, with whatever imports it needs.
3. Back in RoleDashboards.tsx, add: export { SuperadminDashboard } from './dashboards/SuperadminDashboard'; where it used to be.
4. Don't change any logic or JSX — copy it exactly as-is.

Watch out for

• This dashboard is the most complex one — it likely uses RegionalAnalyticsView and/or FLNLevelReferenceModal (see Epic: split RoleDashboards.tsx into one file per dashboard #136's other sub-issues). If those have already been moved by the time you start, just import them from their new location instead of RoleDashboards.tsx.

How to check your work

1. cd frontend && npm run lint — no errors.
2. npm run build — succeeds.
3. Run npm run dev, log in as Superadmin, and click through every section — confirm everything renders and works exactly the same as before.

Part of #136.