[T010] [US4] Add requireRole guard to planos/page.tsx

[EmiyaKiritsugu3]

Feature: Financial Role Access Control — Phase 5 (P3)
Story: US4 — Server-side page guards (defense-in-depth)

Update src/app/dashboard/planos/page.tsx:

1. Import requireRole from @/lib/auth
2. Add await requireRole('GERENTE') as the first statement inside the planos page default export, before the return statement that renders the Suspense wrapper

Note: Call at the default export level (not inside PlanosDataWrapper).

Depends on: T005 (requireRole must exist)