Refactor: Move model fetching logic to core UI module

Centralizes the `btnGetModels` click event handler from the main UI script into the `FFUUI.Core` module to improve code organization and separation of concerns.

The handler is updated to use the local state object instead of a global script variable. The logic for updating the model list is also improved to preserve the collection's object reference, ensuring data binding stability.

FFUDevelopment/BuildFFUVM_UI.ps1

@@ -169,89 +169,6 @@ $window.Add_Loaded({
         $script:uiState.Controls.spModelFilterSection.Visibility = 'Collapsed'
         $script:uiState.Controls.lstDriverModels.Visibility = 'Collapsed'
         $script:uiState.Controls.spDriverActionButtons.Visibility = 'Collapsed'
-        $script:uiState.Controls.btnGetModels.Add_Click({
-                $selectedMake = $script:uiState.Controls.cmbMake.SelectedItem
-                $script:uiState.Controls.txtStatus.Text = "Getting models for $selectedMake..."
-                $window.Cursor = [System.Windows.Input.Cursors]::Wait
-                $this.IsEnabled = $false
-                try {
-                    # Get previously selected models from the master list ($script:uiState.Data.allDriverModels)
-                    # This ensures all selected items are captured, regardless of any active filter.
-                    $previouslySelectedModels = @($script:uiState.Data.allDriverModels | Where-Object { $_.IsSelected })
-
-                    # Get newly fetched models for the current make (already standardized)
-                    $newlyFetchedStandardizedModels = Get-ModelsForMake -SelectedMake $selectedMake -State $script:uiState
-
-                    $combinedModelsList = [System.Collections.Generic.List[PSCustomObject]]::new()
-                    $modelIdentifiersInCombinedList = [System.Collections.Generic.HashSet[string]]::new([System.StringComparer]::OrdinalIgnoreCase)
-
-                    # Add previously selected models first to preserve their selection state and order (if any)
-                    foreach ($item in $previouslySelectedModels) {
-                        $combinedModelsList.Add($item)
-                        # Use a composite key of Make and Model for uniqueness tracking
-                        $modelIdentifiersInCombinedList.Add("$($item.Make)::$($item.Model)") | Out-Null
-                    }
-
-                    # Add newly fetched models if they are not already in the combined list (based on Make::Model identifier)
-                    $addedNewCount = 0
-                    foreach ($item in $newlyFetchedStandardizedModels) {
-                        if (-not $modelIdentifiersInCombinedList.Contains("$($item.Make)::$($item.Model)")) {
-                            $combinedModelsList.Add($item)
-                            # Add to HashSet to prevent duplicates if the new list itself has them (though Get-ModelsForMake should try to avoid this)
-                            $modelIdentifiersInCombinedList.Add("$($item.Make)::$($item.Model)") | Out-Null
-                            $addedNewCount++
-                        }
-                    }
-
-                    $script:uiState.Data.allDriverModels = $combinedModelsList.ToArray() | Sort-Object @{Expression = { $_.IsSelected }; Descending = $true }, Make, Model # Sort by selection status, then Make, then Model
-                    $script:uiState.Controls.lstDriverModels.ItemsSource = $script:uiState.Data.allDriverModels
-                    $script:uiState.Controls.txtModelFilter.Text = "" # Clear any existing filter
-
-                    if ($script:uiState.Data.allDriverModels.Count -gt 0) {
-                        $script:uiState.Controls.spModelFilterSection.Visibility = 'Visible'
-                        $script:uiState.Controls.lstDriverModels.Visibility = 'Visible'
-                        $script:uiState.Controls.spDriverActionButtons.Visibility = 'Visible'
-                        $statusText = "Displaying $($script:uiState.Data.allDriverModels.Count) models."
-                        if ($newlyFetchedStandardizedModels.Count -gt 0 -and $addedNewCount -eq 0 -and $previouslySelectedModels.Count -gt 0) {
-                            # This case means new models were fetched, but all were already present in the selected list.
-                            $statusText = "Fetched $($newlyFetchedStandardizedModels.Count) models for $selectedMake; all were already in the selected list. Displaying $($script:uiState.Data.allDriverModels.Count) total selected models."
-                        }
-                        elseif ($addedNewCount -gt 0) {
-                            $statusText = "Added $addedNewCount new models for $selectedMake. Displaying $($script:uiState.Data.allDriverModels.Count) total models."
-                        }
-                        elseif ($newlyFetchedStandardizedModels.Count -eq 0 -and $selectedMake -eq 'Lenovo' ) {
-                            # Handled Lenovo specific no new models found message inside Get-ModelsForMake or if user cancelled prompt
-                            $statusText = if ($previouslySelectedModels.Count -gt 0) { "No new models found for $selectedMake. Displaying $($previouslySelectedModels.Count) previously selected models." } else { "No models found for $selectedMake." }
-                        }
-                        elseif ($newlyFetchedStandardizedModels.Count -eq 0) {
-                            $statusText = "No new models found for $selectedMake. Displaying $($script:uiState.Data.allDriverModels.Count) previously selected models."
-                        }
-                        $script:uiState.Controls.txtStatus.Text = $statusText
-                    }
-                    else {
-                        $script:uiState.Controls.spModelFilterSection.Visibility = 'Collapsed'
-                        $script:uiState.Controls.lstDriverModels.Visibility = 'Collapsed'
-                        $script:uiState.Controls.spDriverActionButtons.Visibility = 'Collapsed'
-                        $script:uiState.Controls.txtStatus.Text = "No models to display for $selectedMake."
-                    }
-                } # End Try
-                catch {
-                    $script:uiState.Controls.txtStatus.Text = "Error getting models: $($_.Exception.Message)"
-                    [System.Windows.MessageBox]::Show("Error getting models: $($_.Exception.Message)", "Error", "OK", "Error")
-                    # Minimal UI reset on error, keep previously selected if any
-                    if ($null -eq $script:uiState.Data.allDriverModels -or $script:uiState.Data.allDriverModels.Count -eq 0) {
-                        $script:uiState.Controls.spModelFilterSection.Visibility = 'Collapsed'
-                        $script:uiState.Controls.lstDriverModels.Visibility = 'Collapsed'
-                        $script:uiState.Controls.spDriverActionButtons.Visibility = 'Collapsed'
-                        $script:uiState.Controls.lstDriverModels.ItemsSource = $null
-                        $script:uiState.Controls.txtModelFilter.Text = ""
-                    }
-                } # End Catch
-                finally {
-                    $window.Cursor = $null
-                    $this.IsEnabled = $true # Re-enable the button
-                } # End Finally
-            })
         $script:uiState.Controls.txtModelFilter.Add_TextChanged({
                 param($sourceObject, $textChangedEventArgs)
                 Search-DriverModels -filterText $script:uiState.Controls.txtModelFilter.Text -State $script:uiState