Update staffing management to enhance payroll and hiring functionalities

- Increased the `MonthlyPayrollCap` from 10,000 to 40,000, allowing for greater flexibility in hiring and subject assignments.
- Revised payroll calculation logic to ensure that staff members are compensated based on their actual weekly hours, with a minimum payment reflecting one full rate.
- Updated documentation to clarify the new payroll structure and its implications for hiring and subject assignments.
- Enhanced tests to validate the new payroll cap and ensure proper functionality in staffing scenarios, including the handling of uncovered subjects.
- Improved localization strings to reflect changes in staffing and payroll terminology.

src/HSchool.Simulation/SimulationOptions.cs

@@ -53,7 +53,7 @@ public sealed class SimulationOptions
     /// Monthly payroll the player may commit. Hire and subject assignment that would exceed it
     /// are rejected immediately; money itself does not move.
     /// </summary>
-    public float MonthlyPayrollCap { get; set; } = 10_000f;
+    public float MonthlyPayrollCap { get; set; } = 40_000f;
 
     /// <summary>
     /// Working days from Monday. Five is Mon–Fri; six adds Saturday; seven is every day.