Improve disk space error message clarity

[mrrobot47]

Enhanced error messages for backup and restore operations to include:

• Required space in both human-readable format (MB/GB) and bytes
• Available free space in both formats
• Additional space needed to complete the operation

This helps users understand exactly how much more disk space they need to free up when encountering disk space errors during backup/restore operations.

Users will now see:

Error: Not enough disk space to take backup.
Required: 50.84 GB (54,598,761,132 bytes)
Available: 32.54 GB (34,940,645,376 bytes)
Additional space needed: 18.30 GB (19,658,115,756 bytes)
Please free up some space and try again.

This makes it much clearer to users exactly how much space they need to free up!

[Copilot]

Pull request overview

This PR enhances error messages for backup and restore operations to provide more detailed disk space information when insufficient space is available. The changes help users understand exactly how much disk space they need to free up by showing required space, available space, and additional space needed in both human-readable format (MB/GB) and bytes.

Key Changes:

• Added a new format_bytes() helper method to convert bytes to human-readable format (B, KB, MB, GB, TB)
• Enhanced error messages in pre_backup_check() to display detailed disk space information
• Enhanced error messages in pre_restore_check() to display detailed disk space information

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