Add comprehensive test suite, fix minor issues, rename function and file names to match approved verbs (#708)

Scripts/Threading/Invoke-DoEvents.ps1

@@ -1,6 +1,6 @@
 # Processes all pending WPF window messages (input, render, etc.) to keep the UI responsive
-# during long-running operations on the UI thread. Equivalent to Application.DoEvents().
-function DoEvents {
+# during long-running operations on the UI thread. Equivalent to Application.Invoke-DoEvents().
+function Invoke-DoEvents {
     if (-not $script:GuiWindow) { return }
     $frame = [System.Windows.Threading.DispatcherFrame]::new()
     $null = [System.Windows.Threading.Dispatcher]::CurrentDispatcher.BeginInvoke(

Scripts/Threading/Invoke-NonBlocking.ps1

@@ -31,7 +31,7 @@ function Invoke-NonBlocking {
                     $ps.Stop()
                     throw "Operation timed out after $TimeoutSeconds seconds"
                 }
-                DoEvents
+                Invoke-DoEvents
                 Start-Sleep -Milliseconds 16
             }
         }