Function format_bytes 

pub fn format_bytes(bytes: u64) -> String

Converts a file size in bytes into a human-readable format.

This function formats byte sizes dynamically into KB, MB, or GB for readability.

Conversion Logic:

• 1,024 bytes → KB
• 1,024 KB → MB
• 1,024 MB → GB

Formatting:

• Uses two decimal places for precision (e.g., "10.43 MB").
• If size is below 1 KB, it is displayed in raw bytes (e.g., "512 bytes").

Parameters:

• bytes: The size in bytes to format.

Returns:

• A String representing the human-readable file size.