[T008] [US3] Fetch role in DashboardLayout and pass to DashboardNav

[EmiyaKiritsugu3]

Feature: Financial Role Access Control — Phase 4 (P2)
Story: US3 — Nav hides financial links for non-GERENTE

Update src/app/dashboard/layout.tsx:

1. After existing supabase.auth.getUser() call, add: const { data: funcionarioPerfil } = await supabase.from('funcionarios').select('role').eq('id', user.id).maybeSingle()
2. Derive const role = funcionarioPerfil?.role ?? 'RECEPCIONISTA' (fail-closed default)
3. Pass role={role} to <DashboardNav role={role} />

Depends on: T007 (DashboardNav must accept role prop)