Implement Remove Stock Functionality

<UserStory> INV003: Remove Stock </UserStory>

<Changes>
    1. Integrated InventoryManagementService into Controller to handle removal of inventory items.
    2. Implemented InventoryManagementService::removeInventoryItem to mark items as INACTIVE in the datastore.
    3. Enhanced AdminMenu with removeInventoryItem workflow:
       - Displays inventory list with index, ID, part name, quantity, and price.
       - Allows admin to select item by index for removal.
       - Provides confirmation message after successful deletion.
    4. Added static helper function displayInventoryWithItems in AdminMenu for modularized inventory display.
</Changes>

<Test>

  Precondition:
  1. Admin user is logged into the system.
  2. Inventory contains multiple items with unique IDs.
  3. DataStore is initialized and accessible.

  Steps:
  1. Navigate to Admin Menu and select "Remove Inventory Item".
    - Verify that the system displays all inventory items with ID, part name, quantity, and price.
  2. Select an item by entering its index.
    - Verify that the system removes the item and displays a confirmation message.
  3. Attempt to remove an item with an invalid index.
    - Verify that the system rejects the input and shows an error message.
  4. Navigate to "View Stock Levels".
    - Verify that the removed item no longer appears in the inventory list.
</Test>

<Review>
Sreeja Reghukumar
</Review>

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.cpp

@@ -64,6 +64,7 @@ void Controller::addInventoryItem(const std::string& partName, int quantity, dou
 
 void Controller::removeInventoryItem(const std::string& inventoryItemID)
 {
+    m_inventoryManagementService.removeInventoryItem(inventoryItemID);
 }
 
 util::Map<std::string, const ServiceBooking*> Controller::getServiceBookings()

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.h

@@ -2,6 +2,7 @@
 #include "Map.h"
 #include <string>
 #include "Enums.h"
+#include "InventoryManagementService.h"
 
 class Service;
 class ComboPackage;
@@ -14,6 +15,8 @@ class Notification;
 
 class Controller
 {
+private:
+    InventoryManagementService m_inventoryManagementService;
 public:
     bool login(const std::string& username, const std::string& password);
     void logout();

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

@@ -1 +1,15 @@
 #include "InventoryManagementService.h"
+#include "InventoryItem.h"
+
+void InventoryManagementService::removeInventoryItem(const std::string& inventoryItemID)
+{
+    int index = m_dataStore.getInventoryItems().find(inventoryItemID);
+    if (index != -1)
+    {
+        InventoryItem* item = m_dataStore.getInventoryItems().getValueAt(index);
+        if (item != nullptr)
+        {
+            item->setState(util::State::INACTIVE);
+        }
+    }
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/AdminMenu.cpp

@@ -1,6 +1,8 @@
+#include <iomanip>
 #include "AdminMenu.h"
 #include "InputHelper.h"
 #include "OutputHelper.h"
+#include "InventoryItem.h"
 
 void AdminMenu::showMenu()
 {
@@ -48,8 +50,47 @@ void AdminMenu::addInventoryItem()
 {
 }
 
+static util::Map<std::string, const InventoryItem*>
+filterActiveItems(const util::Map<std::string, const InventoryItem*>& inventoryItems)
+{ }
+
+static void displayInventoryWithItems(util::Map<std::string, const InventoryItem*>& inventoryItems)
+{
+}
+
 void AdminMenu::removeInventoryItem()
 {
+    util::clear();
+    auto inventoryItems = m_controller.getInventoryItems();
+    auto activeItems = filterActiveItems(inventoryItems);
+    int activeItemsSize = activeItems.getSize();
+    if (activeItemsSize == 0)
+    {
+        std::cout << "No items available in Inventory." << std::endl;
+        util::pressEnter();
+        return;
+    }
+    displayInventoryWithItems(activeItems);
+    int itemIndex;
+    std::cout << "Enter the index of the item to remove: ";
+    util::read(itemIndex);
+    if (itemIndex < 1 || itemIndex > activeItemsSize)
+    {
+        std::cout << "Invalid index selected." << std::endl;
+        util::pressEnter();
+        return;
+    }
+    const InventoryItem* selectedItem = inventoryItems.getValueAt(itemIndex - 1);
+    if (selectedItem != nullptr)
+    {
+        if(selectedItem->getState() != util::State::INACTIVE)
+        {
+            std::string selectedItemId = selectedItem->getId();
+            m_controller.removeInventoryItem(selectedItemId);
+            std::cout << "Item " << selectedItem->getPartName() << " removed successfully." << std::endl;
+        }
+    }
+    util::pressEnter();
 }
 
 void AdminMenu::checkStockAvailability()