Add rejection handling and dedicated page for envelopes

Introduced a new rejection flow in `ReceiverPage.razor` to detect
rejected envelopes and redirect users to a dedicated rejection
page (`ReceiverRejectedPage.razor`).

- Added `IsRejected` helper method to check envelope rejection
  status based on current status and history.
- Created `ReceiverRejectedPage.razor` to display rejection
  messages, sender details, and navigation options.
- Implemented localized strings for dynamic rejection messages.
- Designed a visually distinct layout for the rejection page.
- Improved user experience with clear messaging and proper
  handling of invalid or unauthorized access.

EnvelopeGenerator.Server/EnvelopeGenerator.Server/Components/Pages/ReceiverPage.razor

@@ -6,6 +6,7 @@
 @using EnvelopeGenerator.Server.Client.Models.Constants
 @using EnvelopeGenerator.Server.Client.Services
 @using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver
+@using EnvelopeGenerator.Domain.Constants
 @using Microsoft.JSInterop
 @using DevExpress.Blazor
 @using System.Drawing
@@ -510,6 +511,11 @@
             _envelopeReceiver = await PageDataService.GetEnvelopeReceiverAsync(EnvelopeKey);
             if (_envelopeReceiver is null)
                 Logger.LogWarning("Envelope receiver data is null for {EnvelopeKey}", EnvelopeKey);
+            else if (IsRejected(_envelopeReceiver))
+            {
+                Navigation.NavigateTo($"/envelope/{Uri.EscapeDataString(EnvelopeKey)}/rejected", forceLoad: true);
+                return;
+            }
 
             // Build initial report (no signature image yet)
             _report = BuildReport(_pdfBytes, _signatures, capturedSignature: null);
@@ -555,6 +561,16 @@
     }
 
     // ----- Report builder -----
+    static bool IsRejected(EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver.EnvelopeReceiverDto envelopeReceiver)
+    {
+        var status = envelopeReceiver.Envelope?.Status;
+        if (status is EnvelopeStatus.DocumentRejected or EnvelopeStatus.EnvelopeRejected)
+            return true;
+
+        return envelopeReceiver.Envelope?.Histories?.Any(h =>
+            h.Status is EnvelopeStatus.DocumentRejected or EnvelopeStatus.EnvelopeRejected) == true;
+    }
+
     /// <summary>
     /// Builds an XtraReport wrapping the PDF bytes.
     /// If a signature is captured and there are signature fields, the signature image is

EnvelopeGenerator.Server/EnvelopeGenerator.Server/Components/Pages/ReceiverRejectedPage.razor

@@ -0,0 +1,105 @@
+@page "/envelope/{EnvelopeKey}/rejected"
+@rendermode InteractiveServer
+@using EnvelopeGenerator.Application.Resources
+@using EnvelopeGenerator.Domain.Constants
+@using EnvelopeGenerator.Domain.Interfaces
+@using Microsoft.Extensions.Localization
+@inject NavigationManager Navigation
+@inject EnvelopeGenerator.Server.Services.EnvelopeReceiverAuthorizationService ReceiverAuthorizationService
+@inject EnvelopeGenerator.Server.Services.EnvelopeReceiverPageDataService PageDataService
+@inject IStringLocalizer<Resource> UiLocalizer
+
+<div class="envelope-viewer-layout" style="justify-content: center; align-items: center; padding: 1.5rem;">
+    <div style="width: min(920px, 100%); background: rgba(255,255,255,0.96); border-radius: 20px; box-shadow: 0 18px 48px rgba(15,23,42,0.22); overflow: hidden;">
+        <div style="padding: 1.2rem 1.4rem; border-bottom: 1px solid rgba(15,23,42,0.08); background: linear-gradient(135deg, rgba(239,68,68,0.12) 0%, rgba(220,38,38,0.08) 100%);">
+            <div style="font-size: 1rem; font-weight: 700; color: #991b1b;">@L("DocRejected", "Dokument abgelehnt")</div>
+        </div>
+
+        <div style="padding: 2rem 1.5rem;">
+            <div style="display: flex; justify-content: center; margin-bottom: 1rem;">
+                <div style="width: 90px; height: 90px; border-radius: 999px; background: #fee2e2; display: inline-flex; align-items: center; justify-content: center; color: #b91c1c;">
+                    <svg xmlns="http://www.w3.org/2000/svg" width="48" height="48" fill="currentColor" viewBox="0 0 16 16">
+                        <path d="M16 8A8 8 0 1 1 0 8a8 8 0 0 1 16 0zM5.354 4.646a.5.5 0 1 0-.708.708L7.293 8l-2.647 2.646a.5.5 0 0 0 .708.708L8 8.707l2.646 2.647a.5.5 0 0 0 .708-.708L8.707 8l2.647-2.646a.5.5 0 0 0-.708-.708L8 7.293 5.354 4.646z" />
+                    </svg>
+                </div>
+            </div>
+
+            <h2 style="text-align: center; font-size: 1.4rem; color: #7f1d1d; margin-bottom: 0.75rem;">
+                @(_isReadAndConfirm
+                    ? L("RejectionInfo1Confirmation", "Dieses Dokument wurde als nicht bestaetigt markiert.")
+                    : L("RejectionInfo1", "Dieses Dokument wurde abgelehnt."))
+            </h2>
+
+            <p style="text-align: center; margin: 0 auto; max-width: 760px; color: #374151; line-height: 1.6;">
+                @((MarkupString)_messageLine2)
+            </p>
+
+            <div style="margin-top: 1.4rem; text-align: center;">
+                <a href="/" class="btn btn-outline-secondary" style="font-weight: 600;">Portal Startseite</a>
+            </div>
+        </div>
+    </div>
+</div>
+
+@code {
+    [Parameter] public string? EnvelopeKey { get; set; }
+
+    bool _isReadAndConfirm;
+    string _messageLine2 = string.Empty;
+
+    protected override async Task OnInitializedAsync()
+    {
+        if (string.IsNullOrWhiteSpace(EnvelopeKey))
+        {
+            Navigation.NavigateTo("/");
+            return;
+        }
+
+        var user = await ReceiverAuthorizationService.AuthorizeAsync(EnvelopeKey);
+        if (user is null)
+        {
+            Navigation.NavigateTo($"/envelope/login/{Uri.EscapeDataString(EnvelopeKey)}");
+            return;
+        }
+
+        var envelopeReceiver = await PageDataService.GetEnvelopeReceiverAsync(EnvelopeKey);
+        if (envelopeReceiver is null)
+        {
+            Navigation.NavigateTo($"/envelope/{Uri.EscapeDataString(EnvelopeKey)}", forceLoad: true);
+            return;
+        }
+
+        if (!IsRejected(envelopeReceiver))
+        {
+            Navigation.NavigateTo($"/envelope/{Uri.EscapeDataString(EnvelopeKey)}", forceLoad: true);
+            return;
+        }
+
+        _isReadAndConfirm = envelopeReceiver.Envelope?.IsReadAndConfirm() ?? false;
+
+        var senderName = envelopeReceiver.Envelope?.User is null
+            ? string.Empty
+            : $"{envelopeReceiver.Envelope.User.Prename} {envelopeReceiver.Envelope.User.Name}".Trim();
+        var senderEmail = envelopeReceiver.Envelope?.User?.Email ?? string.Empty;
+        var envelopeTitle = envelopeReceiver.Envelope?.Title ?? string.Empty;
+
+        var template = L("RejectionInfo2", "Das Dokument \"{2}\" von {0} ({1}) wurde abgelehnt.");
+        _messageLine2 = string.Format(template, senderName, senderEmail, envelopeTitle);
+    }
+
+    static bool IsRejected(EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver.EnvelopeReceiverDto envelopeReceiver)
+    {
+        var status = envelopeReceiver.Envelope?.Status;
+        if (status is EnvelopeStatus.DocumentRejected or EnvelopeStatus.EnvelopeRejected)
+            return true;
+
+        return envelopeReceiver.Envelope?.Histories?.Any(h =>
+            h.Status is EnvelopeStatus.DocumentRejected or EnvelopeStatus.EnvelopeRejected) == true;
+    }
+
+    string L(string key, string fallback)
+    {
+        var value = UiLocalizer[key];
+        return value.ResourceNotFound ? fallback : value.Value;
+    }
+}