Fixed Reviewed Changes

<User Story> Complete Payments - 1797</User Story>

<Changes>
1. Added Controller::getAllInvoices
   - Retrieves all invoices from PaymentManagementService and returns them as a read-only map.
2. Implemented Controller::confirmPayment
   - Delegates payment confirmation for a given invoice ID to PaymentManagementService.
3. Introduced PaymentManagementService::getAllInvoice
   - Provides access to all invoices stored in the datastore.
4. Added PaymentManagementService::confirmPayment
   - Confirms payment for a specific invoice, updates payment date and status, and sends notification.
5. Extended util::PaymentStatus enum
   - Added PAID status and updated string conversion.
6. Integrated AdminMenu::confirmPayment
   - Validates invoice list, filters by status, allows selection, and confirms payment.
7. Updated CustomerMenu::completePayments
   - Uses parameterized status filtering for invoice selection.
8. Enhanced MenuHelper::selectInvoiceFromUserForPayment
   - Accepts requiredStatus parameter for flexible filtering.
9. Adjusted AdminMenu options
   - Added "Confirm Payment" before Logout.
</Changes>

<Test>
Acceptance Criteria:
1. Admin selects "Confirm Payment" from menu.
   - Verify system prompts and displays invoices filtered by status.
2. Admin selects invoice with status = PAID.
   - Verify payment confirmation updates date, sets status, and sends notification.
3. Admin attempts confirmation with empty invoice list.
   - Verify error message: "No pending invoices available for confirmation."
4. Customer completes payment.
   - Verify selection uses util::PaymentStatus::PENDING and payment flow works correctly.
5. Invalid invoice ID entered.
   - Verify system throws runtime_error with "Payment failed: invalid invoice ID."

Precondition:
1. Admin logged into system.
2. At least one invoice exists in datastore.
3. Notification system available.

Steps:
1. Navigate to Admin menu → Confirm Payment.
2. Select invoice with PAID status.
3. Confirm payment and check notification.
4. Attempt with empty invoice list.
5. Attempt with invalid invoice ID.
</Test>

<Review>
Sreeja Reghukumar
</Review>

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Validator.cpp

@@ -116,13 +116,15 @@ bool util::isPasswordValid(const std::string& password)
  *     usersMap - map of user objects keyed by identifier
  * Returns:
  *     bool - true if the username is already in use by an active user, false otherwise
+ * Notes:
+ *     - Only considers users with state util::State::ACTIVE
  */
 bool util::isUsernameDuplicate(const std::string& username, const util::Map<std::string, User*>& usersMap)
 {
     int index = usersMap.findIf(
         [&](const std::string&, User* user)
         {
-            return (user->getUserName() == username);
+            return (user->getUserName() == username && user->getState() == util::State::ACTIVE);
         }
     );
     return index != -1;