Add PDF printing functionality to editor components

Enabled PDF printing in `SenderPdfImageEditor` and `SenderPdfImageEditorToolbar`. Added `CanPrintPdf` property to determine print availability and a new `OnPrintPdfAsync` method for handling print logic via JavaScript interop. Updated the toolbar with a "Print" button that triggers the print functionality.

Implemented the `printDataUrlPdf` function in `envelope-editor.js` to handle printing from a data URL. This function creates an iframe, loads the PDF, and invokes the browser's print functionality with proper cleanup of resources.

EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/PdfEditor/SenderPdfImageEditor.razor

@@ -25,7 +25,9 @@
                                         ZoomIn="OnZoomInAsync"
                                         SetZoomPercent="OnSetZoomPercentAsync"
                                         CanDownloadPdf="@CanDownloadPdf"
-                                        DownloadPdf="OnDownloadPdfAsync" />
+                                        CanPrintPdf="@CanPrintPdf"
+                                        DownloadPdf="OnDownloadPdfAsync"
+                                        PrintPdf="OnPrintPdfAsync" />
         </div>
     }
 
@@ -150,6 +152,7 @@
     private const int MaxZoomPercent = 300;
     private const int ZoomStepPercent = 5;
     private bool CanDownloadPdf => !string.IsNullOrWhiteSpace(PdfDataUrl);
+    private bool CanPrintPdf => !string.IsNullOrWhiteSpace(PdfDataUrl);
 
     private static string GetFieldStyle(SenderPdfFieldOverlay field, double pageWidthPt, double pageHeightPt)
     {
@@ -397,6 +400,17 @@
             "application/pdf");
     }
 
+    private async Task OnPrintPdfAsync()
+    {
+        if (string.IsNullOrWhiteSpace(PdfDataUrl))
+            return;
+
+        await JSRuntime.InvokeVoidAsync(
+            "envelopeEditor.printDataUrlPdf",
+            PdfDataUrl,
+            "application/pdf");
+    }
+
     private void OnEditorMouseUp(MouseEventArgs args)
     {
         _draggedFieldIndex = null;

EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/PdfEditor/SenderPdfImageEditorToolbar.razor

@@ -86,7 +86,7 @@
     </div>
 
     <div class="sender-image-toolbar__group sender-image-toolbar__group--actions" role="group" aria-label="Document actions">
-        <button type="button" class="sender-image-toolbar__icon-btn" title="Print" disabled>
+        <button type="button" class="sender-image-toolbar__icon-btn" title="Print" disabled="@(!CanPrintPdf)" @onclick="PrintPdfAsync">
             <svg xmlns="http://www.w3.org/2000/svg" width="22" height="22" viewBox="0 0 24 24" fill="none" aria-hidden="true">
                 <path d="M7 9V4H17V9" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" />
                 <rect x="5" y="9" width="14" height="8" rx="2" stroke="currentColor" stroke-width="2" />
@@ -150,9 +150,15 @@
     [Parameter]
     public bool CanDownloadPdf { get; set; }
 
+    [Parameter]
+    public bool CanPrintPdf { get; set; }
+
     [Parameter]
     public EventCallback DownloadPdf { get; set; }
 
+    [Parameter]
+    public EventCallback PrintPdf { get; set; }
+
     private int CurrentPageDisplay => CurrentPage > 0 ? CurrentPage : 0;
     private int TotalPagesDisplay => TotalPages > 0 ? TotalPages : 0;
     private int ZoomPercentDisplay => ZoomPercent > 0 ? ZoomPercent : 100;
@@ -238,4 +244,10 @@
         if (DownloadPdf.HasDelegate)
             await DownloadPdf.InvokeAsync();
     }
+
+    private async Task PrintPdfAsync()
+    {
+        if (PrintPdf.HasDelegate)
+            await PrintPdf.InvokeAsync();
+    }
 }