feat(sender-editor): add PDF page rendering pipeline

EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Program.cs

@@ -43,6 +43,7 @@ builder.Services.AddSingleton<AppVersionService>();
 builder.Services.AddScoped<EnvelopeService>();
 builder.Services.AddScoped<LocalizationService>();
 builder.Services.AddScoped<ReceiverService>();
+builder.Services.AddScoped<PdfRenderService>();
 
 // UI Preferences & Theme
 builder.Services.AddScoped<UserPreferencesService>();

EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Services/PdfRenderService.cs

@@ -0,0 +1,32 @@
+using System.Net.Http.Json;
+using System.Text.Json;
+using EnvelopeGenerator.Application.Common.Dto;
+
+namespace EnvelopeGenerator.Server.Client.Services;
+
+public class PdfRenderService(IHttpClientFactory httpClientFactory)
+{
+    private static readonly JsonSerializerOptions _jsonOptions = new(JsonSerializerDefaults.Web);
+
+    public async Task<IReadOnlyList<PdfPageImageDto>> RenderPagesAsync(byte[] pdfBytes, CancellationToken cancel = default)
+    {
+        using var http = httpClientFactory.CreateClient("EnvelopeGenerator.Server");
+        using var response = await http.PostAsJsonAsync(
+            "/api/PdfRender/pages",
+            new PdfRenderRequestDto { PdfBytes = pdfBytes },
+            _jsonOptions,
+            cancel);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            var statusCode = (int)response.StatusCode;
+            var reasonPhrase = response.ReasonPhrase ?? "Unknown error";
+            throw new HttpRequestException(
+                $"Failed to render PDF pages. Status: {statusCode} ({reasonPhrase})",
+                null,
+                response.StatusCode);
+        }
+
+        return await response.Content.ReadFromJsonAsync<List<PdfPageImageDto>>(_jsonOptions, cancel) ?? [];
+    }
+}