Add confirmation popup for clearing signature fields

Added a confirmation popup to `SenderEditorPage.razor` for clearing all signature fields, requiring user confirmation before proceeding. Updated resource files (`Resource.de-DE.resx`, `Resource.en-US.resx`, `Resource.fr-FR.resx`) with localized confirmation messages. Modified the "Remove all signature fields" button to trigger the popup instead of directly invoking the clear action.

Introduced a new `_clearFieldsConfirmVisible` variable to manage popup visibility. Updated the `ClearAllFieldsAsync` method to close the popup before clearing fields. Added new CSS styles in `envelope-viewer.css` to style the confirmation popup and its elements.

EnvelopeGenerator.Application/Resources/Resource.de-DE.resx

@@ -749,6 +749,7 @@
   <data name="SenderEditor_PageLabel" xml:space="preserve"><value>Seite</value></data>
   <data name="SenderEditor_PlaceSignatureField" xml:space="preserve"><value>Signaturfeld platzieren</value></data>
   <data name="SenderEditor_RemoveAllSignatureFields" xml:space="preserve"><value>Alle Signaturfelder entfernen</value></data>
+  <data name="SenderEditor_RemoveAllSignatureFieldsConfirm" xml:space="preserve"><value>Diese Aktion entfernt alle platzierten Signaturfelder unwiderruflich. Fortfahren?</value></data>
   <data name="SenderEditor_SelectPdf" xml:space="preserve"><value>Bitte wählen Sie eine PDF-Datei aus.</value></data>
   <data name="SenderEditor_Sent_Body" xml:space="preserve"><value>Der bestehende Entwurf wurde versendet.</value></data>
   <data name="SenderEditor_Sent_Header" xml:space="preserve"><value>Umschlag gesendet</value></data>

EnvelopeGenerator.Application/Resources/Resource.en-US.resx

@@ -749,6 +749,7 @@
   <data name="SenderEditor_PageLabel" xml:space="preserve"><value>Page</value></data>
   <data name="SenderEditor_PlaceSignatureField" xml:space="preserve"><value>Place signature field</value></data>
   <data name="SenderEditor_RemoveAllSignatureFields" xml:space="preserve"><value>Remove all signature fields</value></data>
+  <data name="SenderEditor_RemoveAllSignatureFieldsConfirm" xml:space="preserve"><value>This action will permanently remove all placed signature fields. Continue?</value></data>
   <data name="SenderEditor_SelectPdf" xml:space="preserve"><value>Please select a PDF file.</value></data>
   <data name="SenderEditor_Sent_Body" xml:space="preserve"><value>The existing draft has been sent.</value></data>
   <data name="SenderEditor_Sent_Header" xml:space="preserve"><value>Envelope sent</value></data>

EnvelopeGenerator.Application/Resources/Resource.fr-FR.resx

@@ -749,6 +749,7 @@
   <data name="SenderEditor_PageLabel" xml:space="preserve"><value>Page</value></data>
   <data name="SenderEditor_PlaceSignatureField" xml:space="preserve"><value>Placer un champ de signature</value></data>
   <data name="SenderEditor_RemoveAllSignatureFields" xml:space="preserve"><value>Supprimer tous les champs de signature</value></data>
+  <data name="SenderEditor_RemoveAllSignatureFieldsConfirm" xml:space="preserve"><value>Cette action supprimera définitivement tous les champs de signature placés. Continuer?</value></data>
   <data name="SenderEditor_SelectPdf" xml:space="preserve"><value>Veuillez sélectionner un fichier PDF.</value></data>
   <data name="SenderEditor_Sent_Body" xml:space="preserve"><value>Le brouillon existant a été envoyé.</value></data>
   <data name="SenderEditor_Sent_Header" xml:space="preserve"><value>Enveloppe envoyée</value></data>

EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Pages/SenderEditorPage.razor

@@ -289,7 +289,7 @@
                 @if (_pdfLoaded && _signatureFields.Count > 0)
                 {
                     <button class="pdf-toolbar__btn pdf-toolbar__btn--reset"
-                            @onclick="ClearAllFieldsAsync"
+                            @onclick='() => _clearFieldsConfirmVisible = true'
                             title='@L("SenderEditor_RemoveAllSignatureFields", "Alle Signaturfelder entfernen")'>
                         <svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" fill="currentColor" viewBox="0 0 16 16">
                             <path d="M5.5 5.5A.5.5 0 0 1 6 6v6a.5.5 0 0 1-1 0V6a.5.5 0 0 1 .5-.5zm2.5 0a.5.5 0 0 1 .5.5v6a.5.5 0 0 1-1 0V6a.5.5 0 0 1 .5-.5zm3 .5a.5.5 0 0 0-1 0v6a.5.5 0 0 0 1 0V6z" />
@@ -506,6 +506,29 @@
     </FooterContentTemplate>
 </DxPopup>
 
+@* ── Clear all fields confirmation popup ── *@
+<DxPopup @bind-Visible="_clearFieldsConfirmVisible"
+         Width="400px"
+         MaxWidth="95vw"
+         ShowHeader="false"
+         ShowFooter="false"
+         CloseOnEscape="true"
+         CloseOnOutsideClick="true">
+    <BodyContentTemplate>
+        <div class="sender-confirm-popup">
+            <p class="sender-confirm-popup__message">@L("SenderEditor_RemoveAllSignatureFieldsConfirm", "Diese Aktion entfernt alle platzierten Signaturfelder unwiderruflich. Fortfahren?")</p>
+            <div class="sender-confirm-popup__actions">
+                <DxButton Text='@L("Cancel", "Abbrechen")'
+                          RenderStyle="ButtonRenderStyle.Secondary"
+                          Click='() => _clearFieldsConfirmVisible = false' />
+                <DxButton Text='@L("Delete", "Löschen")'
+                          RenderStyle="ButtonRenderStyle.Danger"
+                          Click="ClearAllFieldsAsync" />
+            </div>
+        </div>
+    </BodyContentTemplate>
+</DxPopup>
+
 @* ── Save result popup (success + error) ── *@
 <DxPopup @bind-Visible="_savePopupVisible"
          HeaderText='@(_saveErrorMessage is null ? _saveSuccessHeader : L("Error", "Fehler"))'
@@ -620,6 +643,7 @@
     // ── Save state ──
     bool _isSaving = false;
     bool _savePopupVisible = false;
+    bool _clearFieldsConfirmVisible = false;
     string? _saveErrorMessage = null;
     string _saveSuccessHeader = "Erfolg";
     string _saveSuccessTitle = "Vorgang erfolgreich abgeschlossen.";
@@ -1060,6 +1084,7 @@
     // ── Clear all fields ──
     async Task ClearAllFieldsAsync()
     {
+        _clearFieldsConfirmVisible = false;
         _signatureFields.Clear();
         _pendingReceiverForPlacement = null;
         await Task.CompletedTask;

EnvelopeGenerator.Server/EnvelopeGenerator.Server/wwwroot/css/envelope-viewer.css

@@ -2085,3 +2085,21 @@ body.resizing {
 [data-sf-theme="blazing-dark"] .pdf-text-layer ::-moz-selection {
     background: rgba(99, 102, 241, 0.35);
 }
+
+/* ── Confirm popup (headerless, footerless) ── */
+.sender-confirm-popup {
+    padding: 0.25rem 0.25rem 0.5rem;
+}
+
+.sender-confirm-popup__message {
+    margin: 0 0 1.25rem;
+    font-size: 0.9rem;
+    line-height: 1.5;
+    color: var(--bs-body-color, #e2e8f0);
+}
+
+.sender-confirm-popup__actions {
+    display: flex;
+    gap: 0.5rem;
+    justify-content: flex-end;
+}