refactor(tutorial-presents): promote static catalogue to seed-driven TutorialPresentEntries table

The five tutorial gifts every fresh viewer is given at signup used to live as a
static C# array in SVSim.Database/SeedData/TutorialPresents.cs — outside the
seed-JSON pipeline used by all 40+ other globals tables. Editing a gift required
a code change + rebuild instead of a JSON edit + bootstrap re-run.

Now authored in SVSim.Bootstrap/Data/seeds/tutorial-presents.json and loaded into
a new TutorialPresentEntries table via TutorialPresentsImporter (clear-and-rewrite,
mirroring HomeDialogs). ViewerRepository.RegisterAnonymousViewer reads the table
at signup and projects each row into a ViewerPresent with Source="tutorial".

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.Database/Migrations/SVSimDbContextModelSnapshot.cs

@@ -2530,6 +2530,33 @@ namespace SVSim.Database.Migrations
                     b.ToTable("StoryDecks");
                 });
 
+            modelBuilder.Entity("SVSim.Database.Models.TutorialPresentEntry", b =>
+                {
+                    b.Property<string>("PresentId")
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<int?>("ItemType")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Message")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<long>("RewardCount")
+                        .HasColumnType("bigint");
+
+                    b.Property<long>("RewardDetailId")
+                        .HasColumnType("bigint");
+
+                    b.Property<int>("RewardType")
+                        .HasColumnType("integer");
+
+                    b.HasKey("PresentId");
+
+                    b.ToTable("TutorialPresentEntries");
+                });
+
             modelBuilder.Entity("SVSim.Database.Models.UnlimitedRestrictionEntry", b =>
                 {
                     b.Property<long>("Id")