Implement image management enhancements: add functionality to relocate legacy images during startup, update image handling in show metadata, and refactor related API endpoints to utilize the new image storage system. Adjust database schema to support image references and update UI components for improved image selection and display.

backend/src/TeleWave.Infrastructure/Media/ImageDownloader.cs

@@ -0,0 +1,38 @@
+using TeleWave.Application.Common.Interfaces;
+
+namespace TeleWave.Infrastructure.Media;
+
+/// <summary>Скачивает изображение по URL через HTTP-клиент «metadata» и определяет расширение.</summary>
+public sealed class ImageDownloader(IHttpClientFactory httpFactory) : IImageDownloader
+{
+    public async Task<DownloadedImage?> DownloadAsync(string url, CancellationToken cancellationToken)
+    {
+        try
+        {
+            var client = httpFactory.CreateClient("metadata");
+            using var response = await client.GetAsync(url, cancellationToken);
+            if (!response.IsSuccessStatusCode)
+                return null;
+
+            var ext = ExtensionFor(url, response.Content.Headers.ContentType?.MediaType);
+            var bytes = await response.Content.ReadAsByteArrayAsync(cancellationToken);
+            return bytes.Length == 0 ? null : new DownloadedImage(bytes, ext);
+        }
+        catch (Exception ex) when (ex is HttpRequestException or TaskCanceledException or IOException)
+        {
+            return null;
+        }
+    }
+
+    private static string ExtensionFor(string url, string? mediaType) =>
+        mediaType switch
+        {
+            "image/png" => ".png",
+            "image/webp" => ".webp",
+            "image/gif" => ".gif",
+            "image/jpeg" => ".jpg",
+            _ => Path.GetExtension(new Uri(url).AbsolutePath) is { Length: > 1 } e
+                ? e.ToLowerInvariant()
+                : ".jpg",
+        };
+}