Replace selectable name sets with a country that owns names and climate presets.

Create picks a country; climate is rolled from the school seed and stored. Old Slavic saves lift as Russia.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/HSchool.AppHost.Tests/ServiceabilityTests.cs

@@ -37,6 +37,34 @@ public class ServiceabilityTests(AppHostFixture fixture)
         }
     }
 
+    [Fact]
+    public async Task CurrentFormatSave_WithoutCountryId_LeavesTheSchoolUnstartedAndTheFileUntouched()
+    {
+        using var client = fixture.App.CreateHttpClient("server");
+        await SchoolApiTests.ResetAsync(client);
+        var directory = await SavesDirectoryAsync(client);
+
+        try
+        {
+            InstallGolden(directory, "current");
+            var path = Path.Combine(directory, "1.json");
+            BumpFormat(path, 3);
+            var before = File.ReadAllBytes(path);
+
+            using var reload = await client.PostAsync("/api/dev/reload-schools", content: null, TestContext.Current.CancellationToken);
+            reload.EnsureSuccessStatusCode();
+
+            Assert.Empty((await SchoolApiTests.GetSchoolsAsync(client)).Schools);
+            Assert.Equal(before, File.ReadAllBytes(path));
+        }
+        finally
+        {
+            DeleteSchoolFiles(directory, 1);
+            using var cleanup = await client.PostAsync("/api/dev/reload-schools", content: null, TestContext.Current.CancellationToken);
+            cleanup.EnsureSuccessStatusCode();
+        }
+    }
+
     [Fact]
     public async Task CurrentFormatSave_LoadsAsBefore()
     {