Fix PR review comments and refactor menu helper logic

Changes:
- Added name parameter to createTechnician for consistency
- Added function headers for notification-related methods in InventoryManagementService
- Used variables for notification title and message instead of passing strings directly
- Fixed payment reminder notification message formatting
- Moved common helper functions to MenuHelper.h
- Updated CustomerMenu to use shared helper functions instead of duplicate code
- Added missing includes in MenuHelper.h
- Removed redundant helper code from CustomerMenu.cpp
- Minor formatting and comment cleanup

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.cpp

@@ -22,6 +22,14 @@ Date: 22-May-2026
 
 util::Map<std::string, User*> InventoryManagementService::m_observers{};
 
+/*
+Function: attach
+Description: Adds a user to the observer list for receiving inventory notifications.
+Parameters:
+	- user: User*, pointer to the user to be attached as an observer
+Returns:
+	- None
+*/
 void InventoryManagementService::attach(User* user)
 {
 	if (user)
@@ -34,6 +42,14 @@ void InventoryManagementService::attach(User* user)
 	}
 }
 
+/*
+Function: detach
+Description: Removes a user from the observer list so they no longer receive inventory notifications.
+Parameters:
+	- user: User*, pointer to the user to be detached from the observer list
+Returns:
+	- None
+*/
 void InventoryManagementService::detach(User* user)
 {
 	if (user)
@@ -46,6 +62,18 @@ void InventoryManagementService::detach(User* user)
 	}
 }
 
+/*
+Function: sendNotification
+Description: Sends a notification to a user if they are subscribed as an observer.
+Parameters:
+	- user: User*, pointer to the user receiving the notification
+	- title: std::string, title of the notification
+	- message: std::string, body/content of the notification
+Returns:
+	- None
+Throws:
+	- std::runtime_error if notification creation fails
+*/
 void InventoryManagementService::sendNotification(User* user, const std::string& title, const std::string& message)
 {
 	if (user)
@@ -72,20 +100,39 @@ void InventoryManagementService::sendNotification(User* user, const std::string&
 	}
 }
 
+/*
+Function: sendLowStockAlertsToAdmins (static helper)
+Description: Sends low stock alert notifications to all admin users for a given inventory item.
+Parameters:
+	- inventoryManagementService: InventoryManagementService&, service used to send notifications
+	- inventoryItem: const InventoryItem*, pointer to the low-stock inventory item
+	- adminUsers: const util::Vector<User*>&, list of admin users to notify
+Returns:
+	- None
+*/
 static void sendLowStockAlertsToAdmins(InventoryManagementService& inventoryManagementService, const InventoryItem* inventoryItem, const util::Vector<User*>& adminUsers)
 {
 	int adminUsersSize = adminUsers.getSize();
 	for (int index = 0; index < adminUsersSize; index++)
 	{
+		std::string title = "Low Stock Alert";
+		std::string message = "The inventory item with ID " + inventoryItem->getId() + " has very low quantity in the inventory";
 		inventoryManagementService.sendNotification(
 			adminUsers[index],
-			"Low Stock Alert",
-			"The inventory item with ID " + inventoryItem->getId() +
-			" has very low quantity in the inventory"
-			);
+			title,
+			message
+		);
 	}
 }
 
+/*
+Function: sendLowStockAlerts
+Description: Sends alerts to user for inventory items with low stock
+Parameters:
+	- None
+Returns:
+	- None
+*/
 void InventoryManagementService::sendLowStockAlerts()
 {
 	auto& inventoryItems = m_dataStore.getInventoryItems();
@@ -116,7 +163,6 @@ void InventoryManagementService::sendLowStockAlerts()
 	}
 }
 
-
 /*
 Function: getObserverIDs
 Description: Retrieves the IDs of all observers currently attached to the

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp

@@ -19,7 +19,6 @@ Date: 20-May-2026
 #include "User.h"
 #include "Utility.h"
 
-
 util::Map<std::string, User*> PaymentManagementService::m_observers{};
 
 /*
@@ -128,9 +127,9 @@ void PaymentManagementService::sendPaymentReminders()
 					User* customer = serviceBooking->getCustomer();
 					if (customer)
 					{
-						sendNotification(customer,
-							"Payment Reminder",
-							"Your payment for Invoice ID " + invoice->getId() + " is still pending.Please complete the payment." + invoice->getId());
+						std::string title = "Payment Reminder";
+						std::string message = "Your payment for Invoice ID " + invoice->getId() + " is still pending. Please complete the payment.";
+						sendNotification(customer, title, message);
 					}
 				}
 			}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.cpp

@@ -60,9 +60,9 @@ void ServiceManagementService::purchaseService(const util::Vector<std::string>&
 		throw std::runtime_error("Failed to create service booking");
 	}
 	serviceBookingMap[serviceBooking->getId()] = serviceBooking;
-	sendNotification(authenticatedUser,
-		"Service Booking succeeded",
-		"Your service booking has been successfully placed with ID " + serviceBooking->getId());
+    std::string title = "Service Booking succeeded";
+    std::string message = "Your service booking has been successfully placed with ID " + serviceBooking->getId();
+    sendNotification(authenticatedUser, title, message);
 }
 
 /*
@@ -99,9 +99,9 @@ void ServiceManagementService::purchaseComboPackage(const std::string& comboPack
 		throw std::runtime_error("Failed to create combo package service booking");
 	}
 	serviceBookingMap[serviceBooking->getId()] = serviceBooking;
-	sendNotification(authenticatedUser,
-		"Combo Package Service Booking succeeded",
-		"Your service booking for the combo package has been successfully placed with ID " + serviceBooking->getId());
+    std::string title = "Combo Package Service Booking succeeded";
+    std::string message = "Your service booking for the combo package has been successfully placed with ID " + serviceBooking->getId();
+    sendNotification(authenticatedUser, title, message);
 }
 
 util::Map<std::string, User*> ServiceManagementService::m_observers{};