feat(store): populate shops via GetStoreItems

GetStoreItems was a stub returning an empty object, so every shop
(Korolev / ICA / Osiris / QuickShop vendors) showed up empty. Build the
store on the fly from the Blueprints title data: for the requested
StoreId, list every item that declares an ItemShopsCraftingData entry
for that store, converting its currency recipe ingredients into
VirtualCurrencyPrices (SoftCurrency->SC, Aurum->AU, InsuranceCurrency->IN).
Item-ingredient (crafting) entries are left to the crafting UI.

Adds the StoreId/CatalogVersion fields to the request and the
FGetStoreItemsResult / FStoreItem PlayFab response models.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Prospect.Server.Api/Models/Client/FGetStoreItems.cs

@@ -1,8 +1,19 @@
-using System.Text.Json.Serialization;
+using System.Text.Json.Serialization;
 using Prospect.Server.Api.Models.Client.Data;
 
 namespace Prospect.Server.Api.Models.Client;
 
 public class FGetStoreItems
 {
-}
+    /// <summary>
+    ///     [optional] Catalog version to store items from. Use default catalog version if null.
+    /// </summary>
+    [JsonPropertyName("CatalogVersion")]
+    public string? CatalogVersion { get; set; }
+
+    /// <summary>
+    ///     Unique identifier for the store which is being requested.
+    /// </summary>
+    [JsonPropertyName("StoreId")]
+    public string? StoreId { get; set; }
+}