Enhance school creation and staffing management with native language support

- Updated protocol documentation to include `nativeLanguages` in `nameSets` and added `nativeLanguage` to school creation options.
- Enhanced the UI for school creation to allow selection of native languages, improving user experience.
- Revised API interfaces to accommodate new native language features, ensuring proper data handling.
- Improved localization strings to support new native language functionalities in both English and Russian.
- Updated tests to validate the new native language features and ensure robust functionality in staffing scenarios.

tests/HSchool.Content.Tests/VanillaCoreTests.cs

@@ -42,7 +42,7 @@ public class VanillaCoreTests
         Assert.Equal(4, catalog.Subjects["PrimarySchool"].Grades.Max);
         Assert.True(catalog.Subjects.ContainsKey("PhysicalEducation"));
         Assert.NotNull(catalog.StaffingRules);
-        Assert.Equal(12, catalog.StaffingRules.PoolSize);
+        Assert.Equal(32, catalog.StaffingRules.PoolSize);
         Assert.Equal(20, catalog.StaffingRules.BaseWeeklyHours);
         Assert.Equal(36, catalog.StaffingRules.MaxWeeklyHours);
         Assert.NotNull(catalog.DayFrame);