Agent tips are unbounded in number; only the ✕ ($retiredTips) needs to persist, so showTip no longer writes agent: ids into $tipShownAt. Folds the duplicate store test into the first one.
Agent tips are unbounded in number; only the ✕ ($retiredTips) needs to persist, so showTip no longer writes agent: ids into $tipShownAt. Folds the duplicate store test into the first one.