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.

README.md

@@ -119,7 +119,7 @@ Simulation tunables live under the `Simulation` section of
 | `ModsDirectory` | `mods` | pack folders; `core` is required |
 | `SaveIntervalSeconds` | 30 | rare clock snapshot; not every tick |
 | `MinSaveIntervalMilliseconds` | 1000 | shortest gap between saves caused by pause or speed |
-| `MonthlyPayrollCap` | 10000 | monthly payroll the player may commit; hire and extra subjects that would exceed it are rejected |
+| `MonthlyPayrollCap` | 40000 | monthly payroll the player may commit; hires and assignments that would exceed it are rejected |
 | `SchoolWeekDays` | 5 | working days from Monday (5 is Mon–Fri; 6 adds Saturday) |
 
 ## What is deliberately missing