Add document preview feature to wizard popup

Introduced a document preview feature in the `CreateEnvelopeWizardPopup` component. This includes:

- Injected `PdfRenderService` for rendering PDF pages.
- Replaced document metadata display with a preview card.
- Added `SenderPdfImageEditor` for interactive PDF previews.
- Implemented state management for preview pages and overlays.
- Added fallback logic to estimate PDF page count.
- Enhanced `ResetWizardState` to reset preview-related fields.
- Styled the preview card and wrap with new CSS classes.
- Added placeholder event handlers for editor interactions.

EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardPopup.razor

@@ -9,6 +9,7 @@
 @inject IStringLocalizer<Model> ModelLocalizer
 @inject IStringLocalizer<Resource> UiLocalizer
 @inject ReceiverService ReceiverService
+@inject PdfRenderService PdfRenderService
 
 <DxPopup Visible="@_isVisible"
          VisibleChanged="OnPopupVisibleChangedAsync"
@@ -238,10 +239,23 @@
 
                     @if (_documentBytes is not null)
                     {
+                        <div class="sender-create-wizard__document-preview-card">
                             <div class="sender-create-wizard__document-meta">
                                 <div class="sender-create-wizard__document-name">@_documentFileName</div>
                                 <div class="sender-create-wizard__document-size">@_documentSizeText</div>
                             </div>
+                            <div class="sender-create-wizard__document-preview-wrap">
+                                <SenderPdfImageEditor IsPlacementMode="false"
+                                                      PageCount="@_documentPreviewPageCount"
+                                                      Pages="@_documentPreviewPages"
+                                                      PdfDataUrl="@DocumentPreviewDataUrl"
+                                                      PdfFileName="@_documentFileName"
+                                                      Fields="@_documentPreviewFieldOverlays"
+                                                      EditorClick="OnDocumentPreviewEditorClickAsync"
+                                                      RemoveField="OnDocumentPreviewRemoveFieldAsync"
+                                                      MoveField="OnDocumentPreviewMoveFieldAsync" />
+                            </div>
+                        </div>
                     }
                     else
                     {
@@ -331,10 +345,14 @@
     private byte[]? _documentBytes;
     private string? _documentFileName;
     private string _documentSizeText = string.Empty;
+    private int _documentPreviewPageCount;
+    private List<PdfPageImageDto> _documentPreviewPages = [];
     private bool _isDocumentUploading;
     private bool _isStepActionRunning;
     private bool _isFinishing;
 
+    private readonly IReadOnlyList<SenderPdfFieldOverlay> _documentPreviewFieldOverlays = [];
+
     private string? _validationMessage;
 
     private bool IsActionLocked => _isDocumentUploading || _isStepActionRunning || _isFinishing;
@@ -346,6 +364,10 @@
     private IReadOnlyList<RecentReceiverSuggestionDto> FilteredRecentSuggestions =>
         BuildFilteredRecentSuggestions();
 
+    private string? DocumentPreviewDataUrl => _documentBytes is { Length: > 0 }
+        ? $"data:application/pdf;base64,{Convert.ToBase64String(_documentBytes)}"
+        : null;
+
     private string CurrentStepTitle => _currentStep switch
     {
         0 => L("SenderWizard_Step_Basics", "Grunddaten"),
@@ -525,6 +547,22 @@
             _documentBytes = ms.ToArray();
             _documentFileName = file.Name;
             _documentSizeText = FormatSize(_documentBytes.Length);
+
+            _documentPreviewPages = [];
+            try
+            {
+                _documentPreviewPages = (await PdfRenderService.RenderPagesAsync(_documentBytes))
+                    .OrderBy(x => x.PageNumber)
+                    .ToList();
+            }
+            catch
+            {
+                _documentPreviewPages = [];
+            }
+
+            _documentPreviewPageCount = _documentPreviewPages.Count > 0
+                ? _documentPreviewPages.Count
+                : EstimatePdfPageCount(_documentBytes) ?? 1;
         }
         finally
         {
@@ -771,6 +809,51 @@
         return $"{bytes} B";
     }
 
+    private static int? EstimatePdfPageCount(byte[]? documentBytes)
+    {
+        if (documentBytes is null || documentBytes.Length == 0)
+            return null;
+
+        try
+        {
+            var text = System.Text.Encoding.ASCII.GetString(documentBytes);
+            const string marker = "/Type /Page";
+            var count = 0;
+            var index = 0;
+
+            while (true)
+            {
+                index = text.IndexOf(marker, index, StringComparison.Ordinal);
+                if (index < 0)
+                    break;
+
+                count++;
+                index += marker.Length;
+            }
+
+            return count > 0 ? count : null;
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private Task OnDocumentPreviewEditorClickAsync(MouseEventArgs _)
+    {
+        return Task.CompletedTask;
+    }
+
+    private Task OnDocumentPreviewRemoveFieldAsync(int _)
+    {
+        return Task.CompletedTask;
+    }
+
+    private Task OnDocumentPreviewMoveFieldAsync(SenderPdfFieldMoveRequest _)
+    {
+        return Task.CompletedTask;
+    }
+
     private void ResetWizardState()
     {
         _currentStep = 0;
@@ -792,6 +875,8 @@
         _documentBytes = null;
         _documentFileName = null;
         _documentSizeText = string.Empty;
+        _documentPreviewPageCount = 0;
+        _documentPreviewPages = [];
     }
 
     private int? GetDefaultEnvelopeTypeId()

EnvelopeGenerator.Server/EnvelopeGenerator.Server/wwwroot/css/sender-page.css

@@ -1533,6 +1533,28 @@
     padding: 0.55rem 0.7rem;
 }
 
+.sender-create-wizard__document-preview-card {
+    display: flex;
+    flex-direction: column;
+    gap: 0.65rem;
+}
+
+.sender-create-wizard__document-preview-wrap {
+    border: 1px solid rgba(148, 163, 184, 0.38);
+    border-radius: 10px;
+    background: rgba(248, 250, 252, 0.96);
+    height: 320px;
+    overflow: hidden;
+}
+
+.sender-create-wizard__document-preview-wrap .sender-image-editor-shell {
+    height: 100%;
+}
+
+.sender-create-wizard__document-preview-wrap .sender-image-editor {
+    min-height: 0;
+}
+
 .sender-create-wizard__document-name {
     color: #064e3b;
     font-size: 0.85rem;