chore: import upstream snapshot with attribution

Sources/ContainerTestSupport/TemporaryStorage.swift

@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+// Copyright © 2026 Apple Inc. and the container project authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//===----------------------------------------------------------------------===//
+
+import Foundation
+import SystemPackage
+
+public struct TemporaryStorage {
+    public static func withTempDir<T: Sendable>(
+        _ body: @Sendable (FilePath) async throws -> T
+    ) async throws -> T {
+        let url = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
+        defer { try? FileManager.default.removeItem(at: url) }
+        return try await body(FilePath(url.path))
+    }
+}