fix: stop masking fsync failures in the image store

src/image/layer/create.zig

@@ -133,7 +133,9 @@ fn writeTarFromDir(
     }
 
     try file_writer.interface.flush();
-    tar_file.sync(std.Options.debug_io) catch {};
+    // a failed fsync means the layer tar may not be durable; surface it
+    // rather than silently hashing a possibly-unflushed file.
+    tar_file.sync(std.Options.debug_io) catch |err| log.warn("layer tar fsync failed: {}", .{err});
 
     var hash_file = try cwd().openFile(std.Options.debug_io, tar_path, .{});
     defer hash_file.close(std.Options.debug_io);

src/image/registry/blob_transfer.zig

@@ -273,7 +273,9 @@ fn downloadBlobUrlToStore(
         tmp_file.writeStreamingAll(std.Options.debug_io, chunk_buf[0..bytes_read]) catch return error.NetworkError;
     }
 
-    tmp_file.sync(std.Options.debug_io) catch {};
+    // surface a failed fsync — the digest verify below still guards
+    // correctness, but a silent sync failure hides a durability problem.
+    tmp_file.sync(std.Options.debug_io) catch |err| log.warn("blob download fsync failed: {}", .{err});
     try verifyFileDigest(tmp_path, expected);
     blob_store.commitTempBlob(tmp_path, expected) catch return error.NetworkError;
     committed = true;

src/image/store/blob_runtime.zig

@@ -51,7 +51,7 @@ pub fn putBlobFromFile(source_path: []const u8, expected_digest: digest_support.
             break;
         };
     }
-    dest_file.sync(std.Options.debug_io) catch {};
+    dest_file.sync(std.Options.debug_io) catch |err| log.warn("blob copy fsync failed: {}", .{err});
 
     if (!write_ok) {
         cwd().deleteFile(std.Options.debug_io, tmp_path) catch {};
@@ -89,7 +89,7 @@ fn writeToStore(data: []const u8, digest: digest_support.Digest) types.BlobError
         cwd().deleteFile(std.Options.debug_io, tmp_path) catch {};
         return types.BlobError.WriteFailed;
     };
-    file.sync(std.Options.debug_io) catch {};
+    file.sync(std.Options.debug_io) catch |err| log.warn("blob store fsync failed: {}", .{err});
 
     renameTempToBlob(tmp_path, digest) catch return types.BlobError.WriteFailed;
 }