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>

src/HSchool.Server/Api/SchoolEndpoints.cs

@@ -53,7 +53,7 @@ internal static class SchoolEndpoints
                 DateTime.SpecifyKind(request.StartDate, DateTimeKind.Utc),
                 request.ModIds,
                 request.Map,
-                request.NameSetId,
+                request.CountryId,
                 request.NativeLanguage,
                 request.Seed,
                 NewCompletion<SchoolCreationOutcome>());
@@ -77,10 +77,10 @@ internal static class SchoolEndpoints
                     Problem(StatusCodes.Status400BadRequest, "unknown-mod", "A selected mod is missing."),
                 SchoolCreationError.InvalidCatalog =>
                     Problem(StatusCodes.Status400BadRequest, "invalid-catalog", "The selected packs could not be loaded."),
-                SchoolCreationError.UnknownNameSet =>
-                    Problem(StatusCodes.Status400BadRequest, "unknown-name-set", "The selected name set is not in the catalog."),
+                SchoolCreationError.UnknownCountry =>
+                    Problem(StatusCodes.Status400BadRequest, "unknown-country", "The selected country is not in the catalog."),
                 SchoolCreationError.UnknownNativeLanguage =>
-                    Problem(StatusCodes.Status400BadRequest, "unknown-native-language", "The selected native language is not in that name set."),
+                    Problem(StatusCodes.Status400BadRequest, "unknown-native-language", "The selected native language is not in that country."),
                 SchoolCreationError.MissingMod =>
                     Problem(
                         StatusCodes.Status400BadRequest,
@@ -508,7 +508,7 @@ internal sealed record CreateSchoolRequest(
     DateTime StartDate,
     IReadOnlyList<string>? ModIds,
     MapLayout? Map,
-    string? NameSetId,
+    string? CountryId,
     string? NativeLanguage,
     int? Seed);