Enhance staffing management in school simulation by introducing API endpoints for hiring staff and assigning subjects. Implement payroll cap validation to ensure hiring and subject assignments do not exceed the allocated budget. Update the simulation options to include a monthly payroll cap and revise related classes to support new staffing functionalities. Enhance documentation to reflect these changes and update tests to validate the new features.

src/HSchool.People/ApplicantPool.cs

@@ -48,6 +48,14 @@ public sealed record ApplicantPool(int Week, int NextIndex, IReadOnlyList<Applic
         return pool;
     }
 
+    public ApplicantPool Without(string personId) =>
+        this with
+        {
+            Applicants = Applicants
+                .Where(applicant => !applicant.Person.Id.Equals(personId, StringComparison.Ordinal))
+                .ToArray(),
+        };
+
     public static float HourlyAsk(DefCatalog catalog, Person person)
     {
         var rules = catalog.StaffingRules