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.

src/HSchool.Content/PeopleDefValidator.cs

@@ -26,7 +26,7 @@ internal static class PeopleDefValidator
 
         foreach (var names in catalog.NameSets.Values)
         {
-            ValidateNameSet(names);
+            ValidateNameSet(names, catalog);
         }
 
         foreach (var subject in catalog.Subjects.Values)
@@ -171,6 +171,11 @@ internal static class PeopleDefValidator
             throw new ContentLoadException($"SkillDef '{skill.DefName}' has a negative stdDev.");
         }
 
+        if (skill.AdultChance is < 0 or > 1)
+        {
+            throw new ContentLoadException($"SkillDef '{skill.DefName}' adultChance must be 0–1.");
+        }
+
         foreach (var limit in skill.BodyLimits)
         {
             if (string.IsNullOrWhiteSpace(limit.Attribute))
@@ -500,13 +505,41 @@ internal static class PeopleDefValidator
         }
     }
 
-    private static void ValidateNameSet(NameSetDef names)
+    private static void ValidateNameSet(NameSetDef names, DefCatalog catalog)
     {
         if (!NameGrammar.IsKnownPatronymic(names.PatronymicRule))
         {
             throw new ContentLoadException($"NameSetDef '{names.DefName}' has unknown patronymicRule '{names.PatronymicRule}'.");
         }
 
+        foreach (var native in names.Spoken)
+        {
+            if (!catalog.Skills.TryGetValue(native, out var language) || language.Abstract)
+            {
+                throw new ContentLoadException($"NameSetDef '{names.DefName}' native language '{native}' is not a SkillDef.");
+            }
+        }
+
+        if (names.RelatedLanguageChance is < 0 or > 1)
+        {
+            throw new ContentLoadException($"NameSetDef '{names.DefName}' relatedLanguageChance must be 0–1.");
+        }
+
+        if (names.RelatedLanguageStdDev < 0)
+        {
+            throw new ContentLoadException($"NameSetDef '{names.DefName}' relatedLanguageStdDev must not be negative.");
+        }
+
+        if (names.RelatedLanguageMean < 0)
+        {
+            throw new ContentLoadException($"NameSetDef '{names.DefName}' relatedLanguageMean must not be negative.");
+        }
+
+        if (names.RelatedLanguageMax < 0)
+        {
+            throw new ContentLoadException($"NameSetDef '{names.DefName}' relatedLanguageMax must not be negative.");
+        }
+
         if (!NameGrammar.IsKnownGiven(names.DefaultGivenDeclension))
         {
             throw new ContentLoadException($"NameSetDef '{names.DefName}' has unknown defaultGivenDeclension.");