Adjust chart x-axis legend placement

Move the date legend inward to align with the y-axis label on overview and user detail charts.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/src/features/stats/Stats.tsx

@@ -44,7 +44,8 @@ const Stats = () => {
         axisBottom={{
           format: "%b %Y",
           legend: "Date",
-          legendOffset: -40,
+          legendPosition: "middle",
+          legendOffset: -20,
         }}
         useMesh
         pointLabelYOffset={0}