feat: Complete InventoryWizard i18n translation with extended field support

Add comprehensive translation keys for all inventory wizard fields and complete
the InventoryWizard component translation from English/Spanish/Basque.

Translation additions (en/es/eu):
- Extended inventory.fields with 48 new field labels and placeholders:
  * Pricing fields (averageCost, standardCost, sellingPrice, minimumPrice)
  * Inventory management fields (lowStockThreshold, reorderPoint, etc.)
  * Product info fields (packageSize, shelfLifeDays, displayLifeHours, etc.)
  * Storage fields (storageInstructions, handlingInstructions, isPerishable)
  * Supplier fields (preferredSupplierId, supplierProductCode)
  * Quality fields (allergenInfo, nutritionalInfo, certifications)
  * Physical properties (weight, volume, dimensions, color)
  * Status tracking (isActive, trackByLot, trackByExpiry, allowNegativeStock)
  * Additional fields (notes, tags, customFields)

- Added ingredientCategories with 10 options (flour, dairy, eggs, fats, etc.)
- Added productCategories with 5 options (bread, pastry, cake, cookies, specialty)

InventoryWizard implementation:
- Translated all section headers (11 sections)
- Translated all field labels (58 fields)
- Translated all placeholder texts (35 placeholders)
- Translated all tooltips using tooltips namespace (11 tooltips)
- Translated ingredient and product category options (15 total)
- Translated wizard step title

Result: Fully internationalized InventoryWizard with complete en/es/eu support
covering all required fields, advanced options, and dynamic category selection.

frontend/src/locales/eu/wizards.json

@@ -27,7 +27,55 @@
       "brand": "Marka",
       "brandPlaceholder": "Marka izena",
       "description": "Deskribapena",
-      "descriptionPlaceholder": "Inbentario elementuaren deskribapen zehatza"
+      "descriptionPlaceholder": "Inbentario elementuaren deskribapen zehatza",
+      "averageCost": "Batez Besteko Kostua (€)",
+      "lastPurchasePrice": "Azken Erosketa Prezioa (€)",
+      "standardCost": "Kostu Estandarra (€)",
+      "sellingPrice": "Salmenta Prezioa (€)",
+      "minimumPrice": "Gutxieneko Prezioa (€)",
+      "lowStockThreshold": "Stock Baxuko Atalasea",
+      "reorderPoint": "Berriro Eskatzeko Puntua",
+      "reorderQuantity": "Berriro Eskatzeko Kantitatea",
+      "maxStockLevel": "Gehienezko Stock Maila",
+      "leadTimeDays": "Entrega Denbora (egunak)",
+      "packageSize": "Pakete Tamaina",
+      "packageSizePlaceholder": "Adib: 25kg zorroa, 12ko paketea",
+      "shelfLifeDays": "Bizi Iraupena (egunak)",
+      "displayLifeHours": "Erakusketaren Iraupena (orduak)",
+      "storageTempRange": "Biltegiratze Tenperatura Eremua (°C)",
+      "storageTempMin": "Gutx",
+      "storageTempMax": "Geh",
+      "storageInstructions": "Biltegiratze Jarraibideak",
+      "storageInstructionsPlaceholder": "Adib: Gorde leku fresko eta lehorrean eguzki-argitik urrun",
+      "handlingInstructions": "Maneiatzeko Jarraibideak",
+      "handlingInstructionsPlaceholder": "Maneiatzeko eskakizun bereziak",
+      "isPerishable": "Elementu Hondagarria",
+      "preferredSupplierId": "Hornitzaile Hobetsiko ID",
+      "preferredSupplierIdPlaceholder": "Hornitzailearen ID",
+      "supplierProductCode": "Hornitzailearen Produktu Kodea",
+      "supplierProductCodePlaceholder": "Hornitzailearen produktu kodea",
+      "allergenInfo": "Alergenoen Informazioa",
+      "allergenInfoPlaceholder": "glutena, esnea, arrautzak",
+      "nutritionalInfo": "Nutrizio Informazioa",
+      "nutritionalInfoPlaceholder": "kaloriak:250, proteina:8g, karbohidratoak:45g",
+      "certifications": "Ziurtagiriak",
+      "certificationsPlaceholder": "Organikoa, GMO gabea, Kosher",
+      "weight": "Pisua (kg)",
+      "volume": "Bolumena (L)",
+      "dimensions": "Dimentsioak (L×Z×A cm)",
+      "dimensionsPlaceholder": "30×20×15",
+      "color": "Kolorea",
+      "colorPlaceholder": "Produktuaren kolorea",
+      "isActive": "Elementu Aktiboa",
+      "trackByLot": "Lote/Batch-ren arabera jarraitu",
+      "trackByExpiry": "Iraungitze Dataren arabera jarraitu",
+      "allowNegativeStock": "Stock Negatiboa Baimendu",
+      "notes": "Oharrak",
+      "notesPlaceholder": "Elementu honi buruzko ohar gehigarriak",
+      "tags": "Etiketak",
+      "tagsPlaceholder": "organikoa, premium, denborakoa",
+      "customFields": "Eremu Pertsonalizatuak (JSON)",
+      "customFieldsPlaceholder": "{\"eremu_pertsonalizatua\": \"balioa\"}"
     },
     "sections": {
       "basicInformation": "Oinarrizko Informazioa",
@@ -59,6 +107,27 @@
       "dozen": "Dozena",
       "lb": "Libratok (lb)",
       "oz": "Ontzak (oz)"
+    },
+    "ingredientCategories": {
+      "select": "Hautatu...",
+      "flour": "Irinak",
+      "dairy": "Esnekiak",
+      "eggs": "Arrautzak",
+      "fats": "Gantzak eta Olioak",
+      "sweeteners": "Gozo-gailuak",
+      "additives": "Gehigarriak",
+      "fruits": "Frutak",
+      "nuts": "Fruitu Lehorrak eta Haziak",
+      "spices": "Espezia",
+      "leavening": "Altxatzeko Agenteak"
+    },
+    "productCategories": {
+      "select": "Hautatu...",
+      "bread": "Ogia",
+      "pastry": "Gozogintzak",
+      "cake": "Tartak",
+      "cookies": "Galetak",
+      "specialty": "Elementu Bereziak"
     }
   },
   "qualityTemplate": {