formatTokens function
Formats a token count compactly (999, 12.3k, 1.2M).
Returns _unknownLabel for null.
Implementation
String formatTokens(int? tokens) {
if (tokens == null) return _unknownLabel;
if (tokens < 1000) return '$tokens';
if (tokens < 1000000) return '${_trim(_scale(tokens, 1000))}k';
return '${_trim(_scale(tokens, 1000000))}M';
}