AUC of a Signal Ranker with Ties

A model scores 8 trade signals. Four are good (positive class) with scores $0.9,\ 0.6,\ 0.6,\ 0.3$, and four are bad (negative class) with scores $0.8,\ 0.6,\ 0.2,\ 0.1$.

Compute the area under the ROC curve (AUC). Treat tied positive-negative pairs as half a win. Give the answer as a fraction or decimal.