Function parse_exclude_chars 

pub fn parse_exclude_chars(
    exclude_strings: Vec<String>,
) -> Result<Vec<char>, String>

Parses character exclusion strings, expanding ranges like “a-z” or “0-9” Returns a vector of individual characters to exclude

Examples

• “a-z” expands to all lowercase letters
• “0-9” expands to all digits
• “a-c” expands to ‘a’, ‘b’, ‘c’
• “abc” is treated as individual characters ‘a’, ‘b’, ‘c’
• “a-z,0-9,b” combines ranges and individual characters