Enhance people management tests and fix related issues

- Updated `PeopleApiTests` to correctly handle family structures, ensuring tests account for single-parent scenarios and sorting behavior for surnames.
- Added a new test to validate roster integrity after the yearly intake, confirming that the composition reflects changes post-intake.
- Revised assertions to ensure accurate comparisons of student and family data, improving test reliability.
- Enhanced documentation within tests to clarify the purpose and expected outcomes of new functionalities.
- Addressed discrepancies between design and implementation regarding the layout of the people management interface.

tests/HSchool.People.Tests/ApplicantPoolTests.cs

@@ -66,6 +66,26 @@ public class ApplicantPoolTests
         Assert.True(ApplicantPool.HourlyAsk(catalog, strong) > ApplicantPool.HourlyAsk(catalog, weak));
     }
 
+    /// <summary>
+    /// design/staffing.md prices an hour from skills *and* traits — the self-assured ask for more.
+    /// Skills are covered above; this pins the trait half, which core sets on Leader (+10),
+    /// HotTempered (+6) and Quiet (-8).
+    /// </summary>
+    [Fact]
+    public void ConfidentTraits_AskForMoreAndQuietOnesForLess()
+    {
+        var catalog = Fixtures.Catalog();
+        var person = Fixtures.Generate(Fixtures.Classrooms(1)).People.First(candidate => candidate.IsParent);
+        var plain = person with { Traits = [] };
+        var leader = person with { Traits = ["Leader"] };
+        var quiet = person with { Traits = ["Quiet"] };
+
+        var plainAsk = ApplicantPool.HourlyAsk(catalog, plain);
+
+        Assert.Equal(plainAsk + 10f, ApplicantPool.HourlyAsk(catalog, leader), 0.01f);
+        Assert.Equal(plainAsk - 8f, ApplicantPool.HourlyAsk(catalog, quiet), 0.01f);
+    }
+
     [Fact]
     public void GeneratedApplicants_AreNotOnTheRoster_ParentsKeepTheirId()
     {