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/FGetStoreItemsResult.cs

@@ -0,0 +1,25 @@
+using System.Text.Json.Serialization;
+using Prospect.Server.Api.Models.Client.Data;
+
+namespace Prospect.Server.Api.Models.Client;
+
+public class FGetStoreItemsResult
+{
+    /// <summary>
+    ///     [optional] The base catalog that this store is a part of.
+    /// </summary>
+    [JsonPropertyName("CatalogVersion")]
+    public string? CatalogVersion { get; set; }
+
+    /// <summary>
+    ///     [optional] Array of items which can be purchased from this store.
+    /// </summary>
+    [JsonPropertyName("Store")]
+    public List<FStoreItem> Store { get; set; } = new();
+
+    /// <summary>
+    ///     [optional] The ID of this store.
+    /// </summary>
+    [JsonPropertyName("StoreId")]
+    public string? StoreId { get; set; }
+}