feat: Add backward navigation and comprehensive i18n support

- Implement backward navigation in onboarding wizard with state persistence
- Add comprehensive setup wizard translations (Spanish, English, Basque)
- Add configuration widget translations for dashboard
- Support for Suppliers, Recipes, Quality, and Team setup steps

New translation files:
- setup_wizard.json for all 3 languages (es, en, eu)
- Added config section to dashboard.json files

Key improvements:
- Users can now navigate backwards through wizard steps
- All setup wizard steps now have proper i18n support
- Configuration progress widget fully translated

frontend/src/locales/es/dashboard.json

@@ -167,6 +167,30 @@
     "last_30_days": "Últimos 30 días",
     "last_90_days": "Últimos 90 días"
   },
+  "config": {
+    "title": "Completa la Configuración de tu Panadería",
+    "subtitle": "Configura características esenciales para comenzar",
+    "inventory": "Inventario",
+    "suppliers": "Proveedores",
+    "recipes": "Recetas",
+    "quality": "Estándares de Calidad",
+    "add_ingredients": "Agregar al menos {{count}} ingredientes",
+    "add_supplier": "Agregar tu primer proveedor",
+    "add_recipe": "Crear tu primera receta",
+    "add_quality": "Agregar controles de calidad (opcional)",
+    "sections_complete": "secciones completas",
+    "added": "agregado",
+    "recommended": "recomendado",
+    "next_step": "Siguiente Paso",
+    "configure": "Configurar",
+    "features_unlocked": "¡Características Desbloqueadas!",
+    "features": {
+      "inventory_tracking": "Seguimiento de Inventario",
+      "purchase_orders": "Órdenes de Compra",
+      "production_planning": "Planificación de Producción",
+      "cost_analysis": "Análisis de Costos"
+    }
+  },
   "errors": {
     "failed_to_load_stats": "Error al cargar las estadísticas del panel. Por favor, inténtelo de nuevo."
   }