Function validate_positionals_against_meta 

pub fn validate_positionals_against_meta(
    cmd_name: &str,
    specs: &[ArgSpec],
    args: &[Arg],
) -> Result<()>

Validate positional args against a command’s declared specs. Missing required positionals, statically-known type violations, and trailing positionals beyond a fixed-arity spec all fail here; templates, variables, and fragments defer to the runtime resolvers. A trailing Rest spec absorbs any number of positionals.