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.

tests/HSchool.AppHost.Tests/StaffingApiTests.cs

@@ -26,9 +26,9 @@ public class StaffingApiTests(AppHostFixture fixture)
 
         var staffing = await GetStaffingAsync(client, school.Id);
 
-        Assert.Equal(10_000f, staffing.Allocated);
+        Assert.Equal(40_000f, staffing.Allocated);
         Assert.Equal(0f, staffing.Payroll);
-        Assert.Equal(10_000f, staffing.Remaining);
+        Assert.Equal(40_000f, staffing.Remaining);
         Assert.Equal(12, staffing.Applicants.Count);
         Assert.Empty(staffing.Staff);
         Assert.Contains(staffing.Uncovered, subject => subject.DefName == "Mathematics");
@@ -148,9 +148,9 @@ public class StaffingApiTests(AppHostFixture fixture)
         }
 
         Assert.Equal("payroll-exceeded", problem?.Code);
-        Assert.Equal(10_000f, problem?.Allocated);
-        Assert.True(problem?.Payroll <= 10_000f);
-        Assert.True(problem?.Attempted > 10_000f);
+        Assert.Equal(40_000f, problem?.Allocated);
+        Assert.True(problem?.Payroll <= 40_000f);
+        Assert.True(problem?.Attempted > 40_000f);
         Assert.True(staffing.Staff.Count >= 1);
     }
 
@@ -165,7 +165,8 @@ public class StaffingApiTests(AppHostFixture fixture)
         var teacher = hired.Staff.Single();
 
         var assigned = await AssignAsync(client, school.Id, teacher.Id, "Mathematics");
-        Assert.Equal(hired.Payroll, assigned.Payroll);
+        // The first subject already costs: 35 curriculum hours is well past one full rate.
+        Assert.True(assigned.Payroll > hired.Payroll);
 
         assigned = await AssignAsync(client, school.Id, teacher.Id, "RussianLanguage");
         Assert.True(assigned.Payroll > hired.Payroll);