feat(sprint-1-5): cierre Etapa 2 - formatPayback + fixes de marca

- Helper formatPayback con 12 casos cubiertos
- Aplicado en RoiKpiBar, drawRoiKpiCards, csv-export
- Auditoría WCAG: ratio 2.22:1, opción D (font-bold) para Etapa 3
- Adelanto: strings 'InQ ROI' y 'Powered by InQuality' en footers PDF
- Threshold ROI: '1.000%' sin decimal
- 455 tests verdes + 2 E2E

Refs: sprints/sprint-1-5/ETAPA_2_PROMPT.md

src/features/workspace/ResourcesPanel.tsx

@@ -19,7 +19,7 @@ const RESOURCE_TYPE_LABELS: Record<ResourceType, string> = {
 }
 
 const RESOURCE_TYPE_COLORS: Record<ResourceType, string> = {
-  role: 'bg-blue-100 text-blue-700',
+  role: 'bg-slate-100 text-slate-600',
   person: 'bg-green-100 text-green-700',
   system: 'bg-purple-100 text-purple-700',
   equipment: 'bg-amber-100 text-amber-700',