Add View Payslip feature for employees

<UserStory> EMP010 : View Payslip </UserStory>

<Changes>
- Added Timestamp support to Payroll and Payslip models
- Implemented getPayslipForMonth flow from Controller to Service
- Enabled payslip retrieval based on year and month
- Updated menus to allow payslip viewing
- Enhanced MenuHelper with a unified viewPayslip helper
- Added date-based filtering using Timestamp utilities
</Changes>

<Review>
Smitha Mohan
</Review>

Trenser.Zenvy/Trenser.Zenvy/views/EmployeeMenu.cpp

@@ -33,14 +33,14 @@ bool EmployeeMenu::handleOperation(int choice)
 {
 	switch (choice)
 	{
-	/*
-	case 1:
+	
+	/*case 1:
 		m_zenvyController.applyLeave();
-		break;
+		break;*/
 	case 2:
-		m_zenvyController.viewPayslip();
+		viewPayslip(m_zenvyController);
 		break;
-	case 3:
+	/*case 3:
 		m_zenvyController.viewPayslipHistory();
 		break;
 	case 4 :

Trenser.Zenvy/Trenser.Zenvy/views/HRManagerMenu.cpp

@@ -32,6 +32,9 @@ bool HRManagerMenu::handleOperation(int choice)
 {
 	switch (choice)
 	{
+	case 2:
+		viewPayslip(m_zenvyController);
+		break;
 	case 4:
 		viewEmployees(m_zenvyController);
 		break;

Trenser.Zenvy/Trenser.Zenvy/views/ITExecutiveMenu.cpp

@@ -32,6 +32,9 @@ bool ITExecutiveMenu::handleOperation(int choice)
 {
 	switch (choice)
 	{
+	case 2:
+		viewPayslip(m_zenvyController);
+		break;
 	case 4:
 		viewEmployees(m_zenvyController);
 		break;

Trenser.Zenvy/Trenser.Zenvy/views/MenuHelper.h

@@ -296,4 +296,43 @@ inline void searchEmployee(std::shared_ptr<ZenvyController> m_zenvyController)
         std::cout << "No Employee found with this name" << std::endl;
     }
     util::pressEnter();
-}
+}
+
+inline void viewPayslip(std::shared_ptr<ZenvyController> controller)
+{
+    int year, month;
+    util::clear();
+    std::cout << "Enter the year: ";
+    util::read(year);
+    std::cout << "\nEnter the month: ";
+    util::read(month);
+    auto employee = controller->getCurrentEmployee();
+    if (!employee)
+    {
+        std::cout << "No authenticated employee.\n";
+        util::pressEnter();
+        return;
+    }
+    auto result = controller->getPayslipForMonth(employee->getId(), year, month);
+    auto payroll = result.first;
+    auto payslip = result.second;
+    if (payroll && payslip)
+    {
+        std::cout << "\nPayslip for " << employee->getEmployeeName()
+            << " (" << year << "-" << std::setw(2) << std::setfill('0') << month << ")\n\n";
+
+        std::cout << "Basic Salary             : " << payroll->getBasicSalary() << "\n";
+        std::cout << "House Rent Allowance     : " << payroll->getHouseRentAllowance() << "\n";
+        std::cout << "Food Allowance           : " << payroll->getFoodAllowance() << "\n";
+        std::cout << "Employee PF Contribution : " << payroll->getEmployeePFContribution() << "\n";
+        std::cout << "Employer PF Contribution : " << payroll->getEmployerPFContribution() << "\n";
+        std::cout << "----------------------------------------\n";
+        std::cout << "Net Salary (after deductions): " << payslip->getSalary() << "\n";
+        std::cout << "Generated on: " << payslip->getTimestamp().toString() << "\n";
+    }
+    else
+    {
+        std::cout << "Payslip not available for " << year << "-" << month << ".\n";
+    }
+    util::pressEnter();
+}

Trenser.Zenvy/Trenser.Zenvy/views/TalentExecutiveMenu.cpp

@@ -32,6 +32,9 @@ bool TalentExecutiveMenu::handleOperation(int choice)
 {
 	switch (choice)
 	{
+	case 2:
+		viewPayslip(m_zenvyController);
+		break;
 	case 4:
 		viewEmployees(m_zenvyController);
 		break;

Trenser.Zenvy/Trenser.Zenvy/views/TeamExecutiveMenu.cpp

@@ -32,6 +32,9 @@ bool TeamExecutiveMenu::handleOperation(int choice)
 {
 	switch (choice)
 	{
+	case 2:
+		viewPayslip(m_zenvyController);
+		break;
 	case 4:
 		viewEmployees(m_zenvyController);
 		break;

Trenser.Zenvy/Trenser.Zenvy/views/TeamLeadMenu.cpp

@@ -32,6 +32,9 @@ bool TeamLeadMenu::handleOperation(int choice)
 {
 	switch (choice)
 	{
+	case 2:
+		viewPayslip(m_zenvyController);
+		break;
 	case 7:
 		viewEmployees(m_zenvyController);
 		break;