Give each school its own people seed so composition no longer follows create order.

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

src/HSchool.Server/Api/SchoolEndpoints.cs

@@ -55,6 +55,7 @@ internal static class SchoolEndpoints
                 request.Map,
                 request.NameSetId,
                 request.NativeLanguage,
+                request.Seed,
                 NewCompletion<SchoolCreationOutcome>());
             commands.Enqueue(command);
 
@@ -490,12 +491,13 @@ internal sealed record CreateSchoolRequest(
     IReadOnlyList<string>? ModIds,
     MapLayout? Map,
     string? NameSetId,
-    string? NativeLanguage);
+    string? NativeLanguage,
+    int? Seed);
 
-internal sealed record SchoolResponse(int Id, string Name, DateTime GameTime, bool Running, byte SpeedIndex)
+internal sealed record SchoolResponse(int Id, string Name, DateTime GameTime, bool Running, byte SpeedIndex, int Seed)
 {
     public static SchoolResponse From(SchoolState school) =>
-        new(school.Id, school.Name, school.GameTime, school.Running, school.SpeedIndex);
+        new(school.Id, school.Name, school.GameTime, school.Running, school.SpeedIndex, school.Seed);
 }
 
 /// <summary>Everything the main menu needs in one request.</summary>