Pushed an improvement to how season resets are being handled. The backend should now understand if two "rank entries" span the new season boundary, and the frontend will represent this graphically by creating a discontinuity in the line graph.

Made a few quality-of-life improvements that were long overdue, such as showing the daily win-loss record on the tooltip when hovering on the chart, and removing data points from the graph on days where no games were played.