Allow custom BYO app list file paths in UI

Updates the FFU UI and orchestration scripts to allow users to specify custom file paths for their Bring Your Own (BYO) app lists, rather than forcing the use of `UserAppList.json` in a specific directory.

Also modifies the orchestration to sync this custom path via `AppInstallConfig.json` so that the runtime orchestration phase resolves the correct file name and path during installation. Refreshes the Apps ISO if the custom BYO app list is updated.

FFUDevelopment/FFUUI.Core/FFUUI.Core.psm1

@@ -108,6 +108,7 @@ function Get-GeneralDefaults {
     $ffuCapturePath = Join-Path -Path $FFUDevelopmentPath -ChildPath "FFU"
     $officePath = Join-Path -Path $appsPath -ChildPath "Office"
     $appListJsonPath = Join-Path -Path $appsPath -ChildPath "AppList.json"
+    $userAppListPath = Join-Path -Path $appsPath -ChildPath "UserAppList.json"
     $driversJsonPath = Join-Path -Path $driversPath -ChildPath "Drivers.json"
 
     return [PSCustomObject]@{
@@ -163,6 +164,7 @@ function Get-GeneralDefaults {
         InstallApps                    = $false
         ApplicationPath                = $appsPath
         AppListJsonPath                = $appListJsonPath
+        UserAppListPath                = $userAppListPath
         InstallWingetApps              = $false
         BringYourOwnApps               = $false
         # M365 Apps/Office Tab Defaults
@@ -305,6 +307,7 @@ function Update-ApplicationPanelVisibility {
     $subOptionVisibility = if ($installAppsChecked) { 'Visible' } else { 'Collapsed' }
     $State.Controls.applicationPathPanel.Visibility = $subOptionVisibility
     $State.Controls.appListJsonPathPanel.Visibility = $subOptionVisibility
+    $State.Controls.userAppListPathPanel.Visibility = $subOptionVisibility
     $State.Controls.chkInstallWingetApps.Visibility = $subOptionVisibility
     $State.Controls.chkBringYourOwnApps.Visibility = $subOptionVisibility
     $State.Controls.chkDefineAppsScriptVariables.Visibility = $subOptionVisibility