canAdd method
- String categoryRaw
Returns true if another item from the given category can be added.
The categoryRaw string is canonicalized before checking against
balances. Returns true for first-time categories (will be capped
on first addItem call).
Used by UI to enable/disable "Add" buttons.
Implementation
bool canAdd(String categoryRaw) {
final cat = _canon(categoryRaw);
if (!balances.containsKey(cat)) return true; // first time seen -> allowed
return _canAddCanon(cat);
}