Add new route and redirection for PDF.js viewer

Introduce a new route `/report-viewer/{EnvelopeKey}` alongside the existing `/receiver/{EnvelopeKey}`. Add redirection logic in `OnInitializedAsync` to navigate to `/envelope/{key}` for the new PDF.js viewer if `EnvelopeKey` is provided. Ensure this redirection takes precedence over the envelope access check.

EnvelopeGenerator.ReceiverUI/Pages/ReportViewer.razor

@@ -1,4 +1,5 @@
 @page "/receiver/{EnvelopeKey}"
+@page "/report-viewer/{EnvelopeKey}"
 @using System.Drawing
 @using DevExpress.Blazor
 @using DevExpress.Drawing
@@ -320,6 +321,12 @@ Shown="OnPopupShownAsync">
 
     protected override async Task OnInitializedAsync() {
 
+        // ? REDIRECT: /receiver/{key} -> /envelope/{key} (NEW PDF.js viewer)
+        if (!string.IsNullOrWhiteSpace(EnvelopeKey)) {
+            Navigation.NavigateTo($"/envelope/{Uri.EscapeDataString(EnvelopeKey)}", forceLoad: false);
+            return;
+        }
+
         if (!string.IsNullOrWhiteSpace(EnvelopeKey)) {
             var hasAccess = await AuthService.CheckEnvelopeAccessAsync(EnvelopeKey);
             if (!hasAccess) {