Create a command-line tool /app/backup that performs checksum-verified backup and restore operations on a…

Create a command-line tool /app/backup that performs checksum-verified backup and restore operations on a…: a task in TermGrade Environments: 1,004 executable Linux tasks (Harbor dataset). Goal: The tool must correctly backup a source directory into a single archive file, and restore that archive…

The task

**Goal:** The tool must correctly backup a source directory into a single archive file, and restore that archive back to an identical directory tree, with every file's integrity verified via SHA-256 checksums.

Part of ai-and/termgrade-environments.