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.

docs/protocol.md

@@ -229,10 +229,18 @@ Money, uncovered subjects, the applicant pool and current staff. Reads the **pub
 roster, applicant snapshot and catalog — it does not post to the worker. Unknown `{id}` is
 `404` `unknown-school`. `?lang=ru|en` labels subjects and positions.
 
-`allocated` is `Simulation:MonthlyPayrollCap`. `payroll` is the sum of each staff member's
-monthly base (`hourlyWageAsk × baseWeeklyHours × weeksPerMonth`) plus
-`extraSubjectSurcharge` of that base for every subject after the first. The cap is checked
-when hiring or assigning, not at month end; money itself does not move.
+`allocated` is `Simulation:MonthlyPayrollCap`. A staff member is paid
+`hourlyWageAsk × weeklyHours × weeksPerMonth`, never less than one full rate
+(`baseWeeklyHours`), and `payroll` is the sum over staff. The cap is checked when hiring or
+assigning, not at month end; money itself does not move.
+
+`weeklyHours` is not stored: it is the curriculum. For every subject assigned to a person,
+`hoursPerWeek` of that subject across the classes that study it, divided between everyone
+teaching it. So a second teacher of a subject halves what the first one carries — and costs.
+
+A subject appears in `uncovered` when nobody teaches it **or** when the people who do cannot
+between them carry its hours (`maxWeeklyHours` each). Both mean the same thing to a player:
+those lessons will not happen.
 
 ```json
 {
@@ -270,7 +278,8 @@ when hiring or assigning, not at month end; money itself does not move.
       "position": "Teacher",
       "positionLabel": "Учитель",
       "hourlyWageAsk": 50,
-      "monthlyPay": 5000,
+      "weeklyHours": 35,
+      "monthlyPay": 7000,
       "subjects": [{ "defName": "Mathematics", "label": "Математика" }]
     }
   ],