NEO-105: Consolidate inventory snapshot clone helper.

Add PlayerInventorySnapshot.Clone() and use it from craft and
encounter completion pre-flight paths (Bugbot PR #144).

server/NeonSprawl.Server/Game/Crafting/CraftOperations.cs

@@ -56,7 +56,7 @@ public static class CraftOperations
             }
         }
 
-        var simulated = CloneSnapshot(snapshot);
+        var simulated = snapshot.Clone();
         foreach (var input in scaledInputs)
         {
             if (!PlayerInventoryOperations.TrySimulateRemoveStack(ref simulated, input.ItemId, input.Quantity, itemRegistry))
@@ -176,13 +176,6 @@ public static class CraftOperations
         return scaled;
     }
 
-    private static PlayerInventorySnapshot CloneSnapshot(PlayerInventorySnapshot snapshot) =>
-        new()
-        {
-            BagSlots = PlayerInventorySnapshot.CloneSlots(snapshot.BagSlots),
-            EquipmentSlots = PlayerInventorySnapshot.CloneSlots(snapshot.EquipmentSlots),
-        };
-
     private static void CompensatingRestoreInputs(
         string playerId,
         IReadOnlyList<CraftIoApplied> inputs,

server/NeonSprawl.Server/Game/Encounters/EncounterCompletionOperations.cs

@@ -62,7 +62,7 @@ public static class EncounterCompletionOperations
             return Deny(EncounterCompletionReasonCodes.InventoryStoreMissing);
         }
 
-        var simulated = CloneSnapshot(snapshot);
+        var simulated = snapshot.Clone();
         foreach (var grant in grants)
         {
             if (!PlayerInventoryOperations.TrySimulateAddStack(
@@ -139,13 +139,6 @@ public static class EncounterCompletionOperations
     private static string MakeIdempotencyKey(string normalizedPlayerId, string normalizedEncounterId) =>
         $"{normalizedPlayerId}:{normalizedEncounterId}";
 
-    private static PlayerInventorySnapshot CloneSnapshot(PlayerInventorySnapshot snapshot) =>
-        new()
-        {
-            BagSlots = PlayerInventorySnapshot.CloneSlots(snapshot.BagSlots),
-            EquipmentSlots = PlayerInventorySnapshot.CloneSlots(snapshot.EquipmentSlots),
-        };
-
     private static void CompensatingRemoveGrants(
         string playerId,
         IReadOnlyList<EncounterGrantApplied> grants,

server/NeonSprawl.Server/Game/Items/PlayerInventorySnapshot.cs

@@ -41,6 +41,14 @@ public sealed class PlayerInventorySnapshot
         return copy;
     }
 
+    /// <summary>Deep-copies bag and equipment slot arrays (NEO-69 craft pre-flight, NEO-105 encounter grant pre-flight).</summary>
+    public PlayerInventorySnapshot Clone() =>
+        new()
+        {
+            BagSlots = CloneSlots(BagSlots),
+            EquipmentSlots = CloneSlots(EquipmentSlots),
+        };
+
     public InventorySlotState[] GetSlots(InventoryContainerKind container) =>
         container == InventoryContainerKind.Equipment ? EquipmentSlots : BagSlots;