Fix overflow by changing integer type to long type in payroll calculation logic

[jeyongsong]

This pull request primarily updates salary and earnings-related data types from Int to Long to better handle larger values and improve data consistency across the application. Additionally, it removes the unused WorkPolicyService dependency from the HomeController.

Data type updates for salary and earnings

• Changed the return type of getDefaultMonthlySalary in EarningsCalculator from Int? to Long?, and updated internal calculations to use Long instead of Int for monthly salary values. (src/main/kotlin/com/moa/service/EarningsCalculator.kt) [1] [2]
• Updated MonthlyEarningsResponse data class to use Long for workedEarnings and standardSalary fields instead of Int. (src/main/kotlin/com/moa/service/dto/MonthlyEarningsResponse.kt)
• Modified WorkdayService to return workedEarnings as Long instead of Int. (src/main/kotlin/com/moa/service/WorkdayService.kt)

Code cleanup

• Removed the unused WorkPolicyService dependency from the HomeController constructor and corresponding import statement. (src/main/kotlin/com/moa/controller/HomeController.kt) [1] [2]

[github-actions]

Test Results

32 tests   32 ✅  0s ⏱️
 3 suites   0 💤
 3 files     0 ❌

Results for commit adf01c5.

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