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/en/dashboard.json

@@ -132,6 +132,30 @@
     "last_30_days": "Last 30 days",
     "last_90_days": "Last 90 days"
   },
+  "config": {
+    "title": "Complete Your Bakery Setup",
+    "subtitle": "Configure essential features to get started",
+    "inventory": "Inventory",
+    "suppliers": "Suppliers",
+    "recipes": "Recipes",
+    "quality": "Quality Standards",
+    "add_ingredients": "Add at least {{count}} ingredients",
+    "add_supplier": "Add your first supplier",
+    "add_recipe": "Create your first recipe",
+    "add_quality": "Add quality checks (optional)",
+    "sections_complete": "sections complete",
+    "added": "added",
+    "recommended": "recommended",
+    "next_step": "Next Step",
+    "configure": "Configure",
+    "features_unlocked": "Features Unlocked!",
+    "features": {
+      "inventory_tracking": "Inventory Tracking",
+      "purchase_orders": "Purchase Orders",
+      "production_planning": "Production Planning",
+      "cost_analysis": "Cost Analysis"
+    }
+  },
   "errors": {
     "failed_to_load_stats": "Failed to load dashboard statistics. Please try again."
   }