Implement review fixes

Changes:

- Updated ServiceManagementService::createJobCard() to prevent duplicate
  "Technician assigned" notifications when multiple job cards exist for
  the same booking.
- Refined job card creation notification to include Job Card ID, Service
  ID, and Booking ID for clearer technician communication.
- Corrected service booking cancellation notification formatting by
  standardizing capitalization and improving message clarity.
- Improved service booking completion notification to explicitly mention
  the booking ID and confirm invoice generation.
- Ensured consistent notification titles and messages across the
  workflow for better user understanding.

Fixes #2114

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

@@ -629,6 +629,7 @@ void ServiceManagementService::createJobCard(const std::string& bookingID, const
     DataStoreLockGuard lock(m_dataStore);
 	UserManagementService m_userManagementService;
 	ServiceBooking* currentBooking = getServiceBooking(bookingID);
+    std::string title, message;
     if (currentBooking == nullptr)
     {
         throw std::runtime_error("Service Booking not available");
@@ -684,18 +685,30 @@ void ServiceManagementService::createJobCard(const std::string& bookingID, const
             trackedCurrentInventoryItem.state = RecordState::MODIFIED;
 		}
 	}
-	currentBooking->setAssignedTechnician(selectedTechnician);
-	currentBooking->setAssignedTechnicianId(selectedTechnician->getId());
+    const User* currentAssignedTechnician = currentBooking->getAssignedTechnician();
+    const std::string& currentAssignedTechnicianId = currentBooking->getAssignedTechnicianId();
+    if (!currentAssignedTechnician && currentAssignedTechnicianId.empty())
+    {
+        currentBooking->setAssignedTechnician(selectedTechnician);
+        currentBooking->setAssignedTechnicianId(selectedTechnician->getId());
+        title = "Technician assigned";
+        message = "A technician has been assigned to your Service Booking with ID " + bookingID;
+        sendNotification(currentBooking->getCustomer(), title, message);
+    }
+
     if (currentBooking->getStatus() == util::ServiceJobStatus::PENDING)
     {
         currentBooking->setStatus(util::ServiceJobStatus::STARTED);
     }
     currentTrackedServiceBooking.state = RecordState::MODIFIED;
-	std::string title = "Job card created";
-	std::string message = "Job card created for the service and you are assigned for that.";
 	JobCard* jobCard = Factory::getObject<JobCard>(bookingID, currentBooking, currentService, serviceID, technicianID, selectedTechnician, util::Timestamp(), util::ServiceJobStatus::STARTED, util::Timestamp());
 	if (jobCard)
 	{
+        title = "Job Card Assigned";
+        message = "A new Job Card (ID: " + jobCard->getId() +
+            ") has been created for Service " + serviceID +
+            " in Booking " + bookingID +
+            ". You have been assigned to this job.";
 		currentTrackedJobCards.insert(jobCard->getId(), util::createNewRecord(jobCard));
 		sendNotification(selectedTechnician, title, message);
 	}
@@ -703,9 +716,6 @@ void ServiceManagementService::createJobCard(const std::string& bookingID, const
 	{
 		throw std::runtime_error("Failed to create job card.");
 	}
-    title = "Technician assigned";
-    message = "A technician has been assigned to your Service Booking with ID " + bookingID;
-    sendNotification(currentBooking->getCustomer(), title, message);
     m_dataStore.saveJobCards();
     m_dataStore.saveServiceBookings();
     m_dataStore.saveInventoryItems();
@@ -852,8 +862,8 @@ void ServiceManagementService::removeServiceBooking(const std::string& bookingID
         {
             if (currentServiceBooking->getStatus() == util::ServiceJobStatus::PENDING)
             {
-                const std::string title = "Service Booking cancelled.";
-                const std::string message = "Service Booking of id " + bookingID + " successfully cancelled.";
+                const std::string title = "Service Booking Cancelled";
+                const std::string message = "Service Booking (ID: " + bookingID + ") has been successfully cancelled";
                 currentServiceBooking->setStatus(util::ServiceJobStatus::CANCELLED);
                 currentTrackedServiceBooking.state = RecordState::MODIFIED;
                 serviceBookingRemoved = true;
@@ -1025,8 +1035,8 @@ void ServiceManagementService::updateJobStatus(const std::string& jobID)
                 currentJob->getBooking()->setStatus(util::ServiceJobStatus::COMPLETED);
                 trackedServiceBookings.getValueAt(trackedServiceBookings.find(bookingId)).state = RecordState::MODIFIED;
                 paymentManagementService.generateInvoice(currentJob->getBooking());
-                std::string title = "Service Booking completed. Invoice Generated.";
-                std::string message = "Services completed for the booking and invoice generated.";
+                std::string title = "Service Booking Completed";
+                std::string message = "Service Booking (ID: " + bookingId + ") has been completed successfully. An invoice has been generated.";
                 sendNotification(currentJob->getBooking()->getCustomer(), title, message);
             }
         }