repo(card): ICardInventoryRepository.CreateCards surface

SVSim.Database/Repositories/Card/ICardInventoryRepository.cs

@@ -18,6 +18,14 @@ public interface ICardInventoryRepository
     ///   <see cref="DestructError"/> when validation fails. On error nothing is written.
     /// </returns>
     Task<DestructOutcome> DestructCards(long viewerId, IReadOnlyDictionary<long, int> destructCounts);
+
+    /// <summary>
+    /// Validate-then-mutate craft of cards from RedEther. Atomic in a transaction; on validation
+    /// failure nothing is written. Routes Card grants through <see cref="Services.RewardGrantService.ApplyAsync"/>
+    /// so the CardCosmeticReward cascade fires for first-time owners.
+    /// </summary>
+    /// <param name="createCounts">cardId → num_to_create. Empty dict is rejected by the caller.</param>
+    Task<CreateOutcome> CreateCards(long viewerId, IReadOnlyDictionary<long, int> createCounts);
 }
 
 /// <summary>
@@ -42,3 +50,28 @@ public enum DestructError
     CardProtected,
     InsufficientCards,
 }
+
+public sealed record CreateOutcome(CreateResult? Result, CreateError? Error)
+{
+    public bool IsSuccess => Result is not null;
+
+    public static CreateOutcome Ok(CreateResult r) => new(r, null);
+    public static CreateOutcome Fail(CreateError e) => new(null, e);
+}
+
+/// <summary>
+/// Outcome of a successful create. <see cref="Grants"/> is the flattened
+/// <see cref="Services.GrantedReward"/> list returned by <see cref="Services.RewardGrantService.ApplyAsync"/>
+/// — one Card entry per crafted cardId plus any cosmetic-cascade entries.
+/// </summary>
+public sealed record CreateResult(
+    ulong NewRedEtherTotal,
+    IReadOnlyList<Services.GrantedReward> Grants);
+
+public enum CreateError
+{
+    UnknownCard,
+    NotCraftable,
+    WouldExceedMaxCopies,
+    InsufficientVials,
+}