Duplicate File Groups

Implement find_duplicate_files(files), a repository scan helper that groups files with identical content.

Requirements

• Input is a dictionary from path to text content.
• Return only duplicate groups with at least two paths.
• Sort paths inside each group.
• Sort groups by their first path.
• Reject empty paths, . segments, .. traversal, and repeated slashes.
• Treat path changes as different files even when content matches.

Example

Constraints

• Keep the scan in memory.
• Work only from the input map.
• Make output deterministic.