fix(gift): drop RowVersion (SQLite incompatible) + restore wire reward_type map

[Timestamp] byte[] doesn't work under SQLite (the test backend) — EF
expects the DB to populate it on insert, but SQLite has no equivalent
of Postgres's xmin. The WHERE Status = Unclaimed filter plus
IInventoryService's viewer-level concurrency is the practical defense;
RowVersion was only a backstop. Regenerated the migration without the
RowVersion column.

Wire reward_type on the gift endpoint uses a gift-specific scheme that
diverges from UserGoodsType for currencies: wire 1 = Crystal (enum=2),
wire 9 = Rupy (enum=9), wire 4 = Item (enum=4). A naked cast resolves
wire 1 to UserGoodsType.RedEther and silently grants the wrong wallet
— restored the explicit WireRewardTypeToUserGoodsType map from the old
tutorial controller.

Retrofits existing GiftControllerTests to call SeedTutorialPresentsAsync
on the new helper (RegisterViewer doesn't auto-seed; only the prod
signup path does). All 7 existing tests pass.

SVSim.UnitTests/Controllers/GiftControllerTests.cs

@@ -16,6 +16,7 @@ public class GiftControllerTests
     {
         using var factory = new SVSimTestFactory();
         long viewerId = await factory.SeedViewerAsync(tutorialState: 31);
+        await factory.SeedTutorialPresentsAsync(viewerId);
         using var client = factory.CreateAuthenticatedClient(viewerId);
 
         var response = await client.PostAsync("/tutorial/gift_top",
@@ -54,6 +55,7 @@ public class GiftControllerTests
         using var factory = new SVSimTestFactory();
         await factory.SeedGlobalsAsync();
         long viewerId = await factory.SeedViewerAsync(tutorialState: 31);
+        await factory.SeedTutorialPresentsAsync(viewerId);
         using var client = factory.CreateAuthenticatedClient(viewerId);
 
         var pre = await factory.GetViewerCurrencyAsync(viewerId);
@@ -100,6 +102,7 @@ public class GiftControllerTests
         using var factory = new SVSimTestFactory();
         await factory.SeedGlobalsAsync();
         long viewerId = await factory.SeedViewerAsync(tutorialState: 31);
+        await factory.SeedTutorialPresentsAsync(viewerId);
         using var client = factory.CreateAuthenticatedClient(viewerId);
 
         var json = $$"""{"present_id_array":["71478626"],"state":1,{{BaseAuthBlock}}}""";
@@ -129,6 +132,7 @@ public class GiftControllerTests
         using var factory = new SVSimTestFactory();
         await factory.SeedGlobalsAsync();
         long viewerId = await factory.SeedViewerAsync(tutorialState: 31);
+        await factory.SeedTutorialPresentsAsync(viewerId);
         using var client = factory.CreateAuthenticatedClient(viewerId);
 
         var json = $$"""{"present_id_array":["71478626","71478627"],"state":1,{{BaseAuthBlock}}}""";
@@ -167,6 +171,7 @@ public class GiftControllerTests
         // 100, not the hardcoded 41 the endpoint used to emit, or the client's tutorial
         // state machine regresses on a no-op retry.
         long viewerId = await factory.SeedViewerAsync(tutorialState: 100);
+        await factory.SeedTutorialPresentsAsync(viewerId);
         using var client = factory.CreateAuthenticatedClient(viewerId);
 
         var json = $$"""{"present_id_array":["71478626"],"state":1,{{BaseAuthBlock}}}""";
@@ -192,6 +197,7 @@ public class GiftControllerTests
         // found and incremented, not duplicated. The (ViewerId, ItemId) unique index
         // added 2026-05-25 would otherwise throw on SaveChanges → 500 to the client.
         await factory.SeedOwnedItemAsync(viewerId, itemId: 1, count: 5, itemName: "PreOwnedItem");
+        await factory.SeedTutorialPresentsAsync(viewerId);
 
         using var client = factory.CreateAuthenticatedClient(viewerId);
 
@@ -224,6 +230,7 @@ public class GiftControllerTests
         using var factory = new SVSimTestFactory();
         await factory.SeedGlobalsAsync();
         long viewerId = await factory.SeedViewerAsync(tutorialState: 31);
+        await factory.SeedTutorialPresentsAsync(viewerId);
         using var client = factory.CreateAuthenticatedClient(viewerId);
 
         var preFirst = await factory.GetViewerCurrencyAsync(viewerId);