chore: import upstream snapshot with attribution

Sources/ContainerizationExtras/FileManager+Temporary.swift

@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+// Copyright © 2025-2026 Apple Inc. and the Containerization 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
+
+extension FileManager {
+    /// Returns a unique temporary directory to use.
+    public func uniqueTemporaryDirectory(create: Bool = true) -> URL {
+        let tempDirectoryURL = temporaryDirectory
+        let uniqueDirectoryURL = tempDirectoryURL.appendingPathComponent(UUID().uuidString)
+        if create {
+            try? createDirectory(at: uniqueDirectoryURL, withIntermediateDirectories: true, attributes: nil)
+        }
+        return uniqueDirectoryURL
+    }
+}