Function build_branch_name 

pub(crate) fn build_branch_name(args: &[&str]) -> Result<String>

Builds a sanitized, lowercased Git branch name from raw arguments.

Transformation:

• Split each argument by ASCII whitespace into tokens.
• Replace unsupported characters with spaces (only alphanumeric plus ‘.’, ‘/’, ‘_’).
• Collapse contiguous spaces inside each token into - separators.
• Discard empty tokens.
• Join resulting tokens with -.

Errors

• sanitization produces an empty string.