feat: enhance release synchronization with cancellation support, error handling, and logging

- Added `CancellationToken` support across SyncService, GithubService, ForgejoService, and ReleaseAssetDownloadService.
- Improved error handling with detailed logging for asset downloads, deletions, and API operations.
- Refactored SyncService for clearer repository and asset synchronization logic.
- Enhanced performance with async file streams and refined conditional checks.

Services/ReleaseAssetDownloadService.cs

@@ -1,19 +1,41 @@
+using Microsoft.Extensions.Logging;
+
 namespace ForgejoReleaseSync.Services;
 
-public class ReleaseAssetDownloadService(HttpClient httpClient)
+public class ReleaseAssetDownloadService(HttpClient httpClient, ILogger<ReleaseAssetDownloadService> logger)
 {
-    public async Task<string> DownloadReleaseAssetAsync(Uri url)
+    public async Task<string> DownloadReleaseAssetAsync(Uri url, CancellationToken token = default)
     {
-        var fileName = Path.GetFileName(url.AbsoluteUri);
-        var filePath = Path.Combine(Path.GetTempPath(), fileName);
-        await using Stream resource = await httpClient.GetStreamAsync(url);
-        await using FileStream fs = new FileStream(filePath, FileMode.OpenOrCreate);
-        await resource.CopyToAsync(fs, 8192);
-        return filePath;
+        try
+        {
+            var fileName = Path.GetFileName(url.AbsoluteUri);
+            var filePath = Path.Combine(Path.GetTempPath(), fileName);
+
+            await using var resource = await httpClient.GetStreamAsync(url, token);
+            await using var fs = new FileStream(
+                filePath, FileMode.Create, FileAccess.Write, FileShare.None, 8192, useAsync: true);
+            await resource.CopyToAsync(fs, token);
+
+            return filePath;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to download asset from {Url}", url);
+            throw;
+        }
     }
 
-    public async Task DeleteReleaseAssetAsync(string downloadPath)
+    public async Task DeleteReleaseAssetAsync(string downloadPath, CancellationToken token = default)
     {
-        File.Delete(downloadPath);
+        try
+        {
+            File.Delete(downloadPath);
+            await Task.CompletedTask;
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to delete asset {Path}", downloadPath);
+            throw;
+        }
     }
 }