Add documentation headers across system modules

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

@@ -1,3 +1,12 @@
+/*
+File: ServiceManagementService.cpp
+Description: Implements the ServiceManagementService class which manages service-related operations
+			 in the Vehicle Service Management System. Provides functionality for attaching/detaching observers
+			 and sending notifications to users regarding service events.
+Author: Trenser
+Date: 20-May-2026
+*/
+
 #include <stdexcept>
 #include "ServiceManagementService.h"
 #include "User.h"
@@ -6,6 +15,14 @@
 
 util::Map<std::string, User*> ServiceManagementService::m_observers{};
 
+/*
+Function: attach
+Description: Attaches a user as an observer to the ServiceManagementService for receiving notifications.
+Parameters:
+	- user: Pointer to the User object to be attached.
+Returns:
+	- void
+*/
 void ServiceManagementService::attach(User* user)
 {
 	if (user)
@@ -18,6 +35,14 @@ void ServiceManagementService::attach(User* user)
 	}
 }
 
+/*
+Function: detach
+Description: Detaches a user from the observer list of the ServiceManagementService.
+Parameters:
+	- user: Pointer to the User object to be detached.
+Returns:
+	- void
+*/
 void ServiceManagementService::detach(User* user)
 {
 	if (user)
@@ -30,6 +55,18 @@ void ServiceManagementService::detach(User* user)
 	}
 }
 
+/*
+Function: sendNotification
+Description: Sends a notification to a user if they are registered as an observer.
+Parameters:
+	- user: Pointer to the User object to receive the notification.
+	- title: Title of the notification.
+	- message: Message content of the notification.
+Returns:
+	- void
+Throws:
+	- std::runtime_error if notification creation fails.
+*/
 void ServiceManagementService::sendNotification(User* user, const std::string& title, const std::string& message)
 {
 	if (user)