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.Content/PeopleDefs.cs

@@ -175,6 +175,17 @@ public sealed class StaffingDef : Def
     public float HourlyWageBase { get; init; }
 
     public float HourlyWagePerSkill { get; init; }
+
+    /// <summary>Hours assumed in the monthly base rate. Extra subjects add a surcharge on top.</summary>
+    public float BaseWeeklyHours { get; init; }
+
+    public float WeeksPerMonth { get; init; }
+
+    /// <summary>
+    /// Added to the monthly base for each subject after the first. <c>0.25</c> means a second
+    /// subject costs 25% of the base rate.
+    /// </summary>
+    public float ExtraSubjectSurcharge { get; init; }
 }
 
 public enum BodyAttributeKind